Report to Congress
on
Railroad Emissions -
A Study Based On Existing Data
Prepared by
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Mobile Sources
Emission Control Technology Division
Standards Development and Support Branch
-------
Report to Congress
on
Railroad Emissions -
A Study Based On Existing Data
Prepared by
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Mobile Sources
Emission Control Technology Division
Standards Development and Support Branch
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Table of Contents
Section Page
1. Introduction 1
2. Summary of Conclusions 4
3. Recommendations Pertaining to Federal Action , . 7
4. Background 8
4.1 Selection of Study Areas 8
4.2 Locomotive Design Characteristics
Pertinent to the Study 8
4.3 Locomotive Duty Cycles 17
4.3.1 Switch and Transfer Locomc-ive
Duty Cycle 19
4.3.2 Line-Haul Locomotive Duty Cycle 21
4.3.3 Secondary Power Source Duty Cycle .... 24
5. Railroad Emission Estimates 27
5.1 Locomotive Exhaust Emissions 27
5.2 Secondary Power Source Exhaust Emissions. 36
6. Environmental Impact of Railroad Emissions ... 44
6.1 Non-Exhaust Emissions 44
6.1.1 Refueling Losses 44
6.2 Exhaust Emissions 45
6.2.1 Localized Effects ..... 45
6.2.1.1 Air Quality Monitoring 46
6.2.1.2 Air Quality Modeling 48
6.2.2 Within AQCRs 48
7. Potential Emission Reduction Techniques 52
7.1 Duty Cycle Modifications 52
7.1.1 Engine Shutdown When Not
in Active Service 52
7.1.2 Limiting Use of Highest Power
Settings When in Urban Areas 56
7.1.3 Composite Effect of Duty
Cycle Modifications ..... 58
7.2 Application of Emission
Control Technology 58
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7.2.1 Modification of Injector Design ..... 59
7.2.2 Modification of Injection Timing
(Timing Retard) 59
7.2.3 Exhaust Gas Recirculation 60
7.2.4 Reduced Scavenging (Increased
Internal Exhaust Gas Recirculation) ... 61
7.2.5 Water Injection 62
8. Cost and Cost-Effectiveness Estimates 64
8.1 Duty Cycle Modifications 64
8.1.1 Engine Shutdown When Not In
Active Service 64
8.1.1.1 Engine Startability 65
8.1.1.2 Use of Antifreeze and Control
of Fuel Waxing 71
8.1.1.3 Cold Start Emissions 75
8.1.1.4 Lubrication Changes 77
8.1.1.5 Fuel Savings from Engine Shutdown .... 78
8.1.1.6 Composite Costs for Engine
Shutdown . 78
8.1.2 Restricted use of High Power Settings
in Urban Areas 80
8.2 Application of Emission Control
Technology 81
8.2.1 Modification of Injector Design 83
8.2.2 Modification of Injection Timing .... 83
8.2.3 Exhaust Gas Recirculation . 83
8.2.4 Reduced Scavenging (Increased Internal
Exhaust Gas Recirculation) 86
8.2.5 Water Injection 87
8.3 Cost-Effectiveness 90
9. Existing State and Local Regulations 99
9.1 Survey of Existing Regulations ..... 99
9.1.1 Survey Returns 99
9.1.2 Types of Regulations 101
9.1.3 Typical Regulation 101
9.1.4 Compilation of State and Local
Standards 103
9.1.5 General Results 105
9.1.6 Subjective Questions on Enforcement . . . 107
9.1.7 Subjective Questions on the
Need for Federal Regulations 108
9.2 Effects of Existing Regulations 109
9.2.1 Health and Welfare 109
9.2.2 Operational and Technical Controls . . . 109
9.2.3 Interstate Commerce Ill
References 113
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List of Illustrations
Figures Page
1. Philadelphia AQCR 9
2. Chicago AQCR . . 10
3. Central Chicago 11
4. St. Louis AQCR 12
5. Kansas City AQCR 13
6. Los Angeles AQCR 14
7. Central Los Angeles 15
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List of Tables
Table Page
1. Switch Locomotive Duty Cycles 20
2. Line-Haul Locomotive Duty Cycles 22
3. Line-Haul Locomotive Duty Cycle Applicable to
Operation Within Air Quality Control Regions ... 23
4. Line-Haul Locomotive Duty Cycles Overall Average,
Within AQCRs and in Rural Areas 25
5. Refrigerated Rail Car Duty Cycle and Engine
Loading 26
6. Average Locomotive Hydrocarbon Emissions by
Throttle Setting 29
7. Average Locomotive Carbon Monoxide
Emissions by Throttle Setting 30
8. Average Locomotive Oxides of Nitrogen
Emissions by Throttle Setting 31
9. In-use Locomotive Power Rating Groups,
Number of Locomotives by Groups and Test
Engines Representing In-Use Groups .33
10. In-Use Weighted Average Line-Haul
Locomotive Emissions by Throttle Position .... 34
11. In-Use Weighted Average Switch and Transfer
Locomotive Emissions by Throttle Position .... 34
12. Line-Haul Locomotive Emissions per
Locomotive per 12-Hour Day in an AQCR 35
13. Switch and Transfer Locomotive Emissions
per Locomotive,24-Hours Per day 35
14. Number of Locomotives in Each AQCR 37
15. Line Haul and Switch and Transfer Locomotive
Emissions in Five ACQRs 38
16. Refrigerated Rail Cars in Each AQCR 40
17. Refrigerated Rail Car Emissions by
Power Setting 42
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18. Refrigerated Rail Car Emissions 42
19. Railroad Emissions in Five AQCRs 43
20. Summary of Air Contaminant Levels in the Cab
of Long-Hood, Forward Switchyard Locomotives ... 47
21. Railroad Emissions, Total Anthropogenic Emissions
and Percentage Contributions by Railroads
for Five AQCRs 49
22. Percentage of Total Railroad Emissions in AQCRs
Contributed by Idle Mode and Notch 8 Operations. . 51
23. Locomotive Fuel Consumption - Average Values
in AQCRs 57
24. Summary of Costs: Engine Starting Aides 72
25. Summary of Costs: Use of Antifreeze and
Fuel Waxing Control 76
26. Summary of Costs: Reducing Cold Start
Emissions and Lubrication Changes 79
27. Summary of Costs: Duty Cycle Modification
Relative to Historical Duty Cycles 82
28. Summary of Costs: Application of
Emission Control Technology 91
29. Percent Change in Lifetime Emissions and Fuel
Consumption By Control Procedure Relative
to Historical Duty Cycles 92
30. Lifetime Change in Mass of Emissions in AQCRs
and Fuel Consumed for An Average Locomotive
Relative to Historical Duty Cycles 93
31. Lifetime Costs for Emission Control
Procedures per Locomotive Relative to
Historical Duty Cycles 94
32. Cost Effectiveness of Control Strategies
Based on Historical Duty Cycles 95
33. Cost Effectiveness for Controlling
Non-Locomotive Sources 97
34. Survey Returns . 100
35. Categorization of State and Local Regulations . 104
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1.0 INTRODUCTION
Section 404 of the Clean Air Act (CAA) Amendments of 1977*
required the Environmental Protection Agency (EPA) to conduct a
study of emissions of air pollutants from railroad locomotives
and secondary rolling stock power sources with respect to: 1)
their environmental impact, 2) methods for control, and 3) the
status and effects of state regulations. The results of the
study, together with recommendations on appropriate legislative
action, were to be reported to the Congress.
This report presents the results of the study performed by
the EPA for five selected Air Quality Control Regions and the
recommendations based upon the findings of the study. Sections
6, 7, and 9 of this report address the three areas of study
which were required by the legislation. Background information
and computational procedures employed are provided in sections
4 and 5. Section 8 provides the estimates of costs and cost
effectiveness associated with the methods which were considered
for reducing railroad emissions.
Information on railroad emissions, state regulations, etc.
was gathered by literature searches, questionnaires, interviews
and from the Association of American Railroads (AAR) and
locomotive manufacturers. This approach was selected as being
the most timely as well as being the most cost-effective
"RAILROAD EMISSION STUDY
Sec.404 (a) The Administrator of the Environmental
Protection Agency shall conduct a study and investigation
of emissions of air pollutants from railroad locomotives,
locomotive engines, and secondary power sources on
railroad rolling stock, in order to determine
(1) The extent to which such emissions affect air
quality control regions throughout the United States,
(2) The technological feasibility and the current state
of technology for controlling such emissions, and
(3) The status and effect of current and proposed state
and local regulations affecting such emissions.
(b) Within one-hundred and eighty days after commencing
such study and investigation, the Administrator shall
submit a report of such study and investigation, together
with recommendations for appropriate legislation, to the
Senate Committee on Environment and Public Works and the
House Committee on Interstate and Foreign Commerce."
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approach in terms of both personnel and financial resources.
The literature searches, and AAR and manufacturer supplied data
were utilized to estimate locomotive and secondary power source
emissions levels, fleet size and distribution, usage patterns
and duty cycles, and fuel consumption.' Questionnaires were
sent to state and local air pollution control agencies to
survey their regulations, enforcement policies and problems and
the perceived need for Federal regulations. Personnel of the
Federal Railroad Administration and industry were interviewed.
Information gathered from the sources was compiled to
develop the reported emissions inventories, air quality
impacts, and effects of state and local regulations on
interstate commerce.
Copies of the original draft of the report were provided,
for review and comment, to the Association of American
Railroads and to the locomotive manufacturers (Electromotive
Division of General Motors (EMD) and General Electric (GE)).
Comments and recommendations provided by the reviewers have,
wherever possible, been incorporated into the report. Briefly,
components of the report which were impacted by the reviewers
recommendations and components where recommendations for change
were made but not incorporated are as follows:
0 Locomotive emissions data base sample size.
Initially, the report had relied on a very small
sample of data collected in 1972. Data collected
from new locomotives and supplied by EMD in 1978 had
not been used because of lack of information on the
effects of locomotive aging on emissions. As a
result of the review, AAR furnished data collected
in 1984 from in-use locomotives. Provision of this
data substantially increased the size of the data
base. It also allowed another increase in the size
of the data base by incorporation of the EMD data.
0 Calculational procedures for estimating locomotive
emissions. Originally, three methods were employed
to calculate locomotive emissions. EPA recognized
that two of the methods were very weak because of
assumptions which had to be employed to utilize the
available data. Because of concerns raised by the
reviewers with respect to the veracity of the
assumptions, two calculational methodologies were
removed from the report.
0 Number of locomotives in AQCRs. EMD expressed the
opinion that the number of locomotives actually in
operation in Air Quality Control Regions are lower
than the numbers utilized in the report. EMD
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expressed the opinion that, for Chicago for example,
the report overestimated the number of. locomotives
in use by a factor of 2.5. This area of the report
was not changed because of lack of data to
substantiate EMD's opinion. This comment should be
borne in mind when reading the report, however,
because the estimates of locomotive emissions in the
AQCRs are directly proportional to the estimates of
the number of locomotives in use in the AQCRs.
Emission control technology effects and costs. EMD
recommended that the report present a generalized
review of technological emission control approaches
and the omission of quantitative values associated
with control technology effects. EMD also expressed
the opinion that reliable cost estimates could not
be developed lacking better understanding of design
changes associated with the application of control
technologies.
While EPA shares the concerns raised by EMD, it is
the opinion of EPA that sufficient information is
available to allow the development of first order
estimates of the effects and costs of control
technologies. These sections of the report were,
therefore, not changed as a result of the reviewers'
comments.
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2.0 SUMMARY OF CONCLUSIONS
Data available in the literature, for utilization in the
performance of the railroad emissions estimates and especially
for projections of emissions reductions achievable, were not
extensive. The results of the study must, therefore, be viewed
as providing indications with respect to the areas of probable
concern and corrections thereof, rather than an exact
determination of the impact of railroad emissions on the
environment.
Conclusions resulting from the performance of this study
are as follows:
1. State and local regulations exist in most localities
for some control of locomotive emissions. The regulations and
their enforcement are directed almost exclusively to visible
emissions (smoke) with little if any attention to invisible
gaseous emissions (i.e., HC, CO, and NOx). The regulations are
directed to the steady-state operations of the locomotives with
provisions for exceeding the standards under those conditions
which are associated with short term and generally higher
emission levels, e.g., during maintenance, after a cold start,
after prolonged periods of idling and during accelerations.
2. There are relatively large differences in the
stringencies of existing regulations. The stringencies of
existing state and local regulations ranged between an opacity
limit of 20 percent for the most stringent standard to an
opacity limit of 60 percent for the least stringent standard.
These differences do not appear to pose significant problems
with respect to interstate commerce, possibly because of either
weak enforcement of the regulations or because the railroads
maintain separate fleets of locomotives for each region. There
was insufficient data to either support or refute a third
possibility, namely that the most stringent standard is easily
achievable.
3. The stringency of enforcement of local regulations
varies from locality to locality.
4. Transferral of locomotives with high smoke emissions
from areas of strict enforcement to areas of either weak or no
enforcement appears to be a practice used by railroads. There
is not sufficient data to determine whether this practice
results in large numbers of high-emitting locomotives being
concentrated in some areas of the nation or whether as a
result, railroad emissions in these areas are higher than would
otherwise be predicted.
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5. There was no particulate emissions data which had
been collected from locomotives. A very small amount of
particulate data were available on two locomotive type engines
which are stationary mounted at Southwest Research Institute.
One engine was an EMD product, the other was a GE product. The
results of what were largely single tests per engine at each
power setting, expressed as grams per brake horsepower hour,
(g/BHP-hr) ranged from a low of 0.24 g/BHP-hr to a high of 2.83
g/BHP-hr. It is not known whether these data are
representative of locomotive particulate emission rates. Since
locomotives use diesel engines, they should possibly be viewed
as sources of concern for particulate emissions.*
6. Railroad emissions estimates developed in this study
indicate that railroad contributions to the total anthropogenic
emissions of hydrocarbons, carbon monoxide and oxides of
nitrogen in the five AQCR's studied are in the following
ranges: for hydrocarbons the range is from just over one tenth
of one percent to one and a third percent; for carbon monoxide
the range is from under one tenth of one percent to one-half of
one percent and for oxides of nitrogen the range is from two
and a third percent to almost fifteen percent. It could not be
determined from the data whether areas of concentrated railroad
activity constituted a significant source of emissions for
adjacent populated areas.
7. Technological approaches for the reduction of NOx
emissions from diesel engines generally result in increased
particulate emissions (smoke) and increased fuel consumption.
Simultaneous reductions in particulate and NOx emissions may be
achievable by derating the power of the locomotive. However,
if derating were to result in the use of a greater number of
locomotives in order to perform the same function (e.g., an
additional locomotive on a train), there could be a net
increase in total emissions in spite of there being a reduction
in emissions from each locomotive.
8. Modification of locomotive duty cycles to reduce the
amount of time that locomotive engines are allowed to idle has
the potential for reducing railroad emissions as well as being
a strategy for fuel conservation. Solutions to several
EPA's Office of Research and Development is presently
developing a health assessment document for diesel engine
emissions. This assessment is being based, in large part,
on new epidemiological studies (references 19 and 20)
involving exposure of railroad workers with support for
diesel particulate exposure by railroad employees derived
from data collected from two locomotive type engines by
Southwest Research Institute.
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technical problems must, however, be developed before this
approach to emission control and fuel conservation can be
employed under all ambient temperatures.
9. The cost-effectiveness of reducing locomotive
emissions appears similar to the cost effectiveness of controls
for automobiles, trucks, and motorcycles, but data for making
these estimates is very limited.
10. Locomotives remain in service for much longer
periods of time than do trucks and passenger cars. If future
emissions data warrants the regulation of locomotive emissions,
consideration should be given to reducing emissions from in-use
locomotives as well as new locomotives.
11. Enforcement of gaseous emissions standards and
particulate standards cannot be performed visually as is
apparently the present practice for smoke emissions.
Development of appropriate test equipment and test cycles
would, therefore, be necessary. Information currently
available does not indicate what level of difficulty or cost
would be associated with the development of test procedures and
their implementation.
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3.0 RECOMMENDATIONS PERTAINING TO FEDERAL ACTION
This study has shown that there is relatively little data
on gaseous emissions and essentially no data on particulate
emissions from locomotives and secondary power sources used by
the railroad industry. The study has also shown that data
pertaining to the application of emission control technology to
locomotive engines is lacking. Estimates made in this study of
railroad emissions, their control, and their impact on air
quality included assumptions in those areas where data were
lacking. While the emissions estimates were inconclusive, they
suggest that railroads could be viewed with some concern as
sources of oxides of nitrogen emissions in some Air Quality
Control Regions. To some lesser extent, hydrocarbon emissions
from railroads may also be of some concern in some Air Quality
Control Regions. Preliminary assessment of technology
indicates that control of these emissions may be cost-effective.
It is recommended that sufficient data on locomotive
emissions be collected to permit an accurate determination of
railroad emissions and their effects. Areas where data
collection needs to be emphasized are: 1) particulate emission
rates, 2) locomotive duty cycles, 3) the distribution of
locomotives throughout the country, and 4) the identification
of local concentrations of high emitting locomotives. It is
further recommended that techniques for the control of
locomotive emissions be evaluated with respect to feasibility
of application to both new and in-use locomotives, cost of
control and impact on railroad operations. Such studies would
reduce the uncertainties contained in present estimates and
allow determination of the need for Federal control of railroad
emissions.
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4.0 BACKGROUND
This section of the report gives a general overview of the
study and identifies some characteristics of locomotives and
their method of operation which are pertinent to emission
patterns of railroad equipment. Modifications of these
characteristics with the objective of reducing .emissions and
fuel consumption constitute part of the section of the report
entitled, "Emission Reduction Techniques."
4 .1 Selection of Study Areas
Three criteria were used in choosing the Air Quality
Control Regions (AQCR) which were analyzed. The first
criterion was to meet the Clean Air Act (CAA) requirement that
the effects of railroads on air quality be investigated on a
nationwide basis. Regions located in several geographic areas
of the country were, therefore, chosen. The second criterion
was that violations of the National Ambient Air Quality
Standards (NAAQS) should either be present in the regions
studied or that the regions should have ambient concentrations
approaching the standards. The third criteria was that the
regions studied should have significant concentrations of
railroad traffic. The second and third criteria were used to
define areas with pollution problems that may be partially
attributable to railroads. It was assumed that if railroads
were shown not to be significant contributors to pollution in
these regions, then they should not be major contributors in
other areas of the country.
Five AQCRs were selected for study on the basis of these
criteria. The AQCRs are: Philadelphia, Chicago, St. Louis,
Kansas City, and Los Angeles. These AQCRs and the included
railroad lines are shown in Figures 1 through 7. These regions
are located throughout the nation. The NAAQS for ozone is
violated in each of these regions. Kansas City, St. Louis, and
Chicago in particular have some of the greatest concentrations
of railroad traffic in the nation. The regions selected
should, therefore, represent a "worst case" for ozone as
related to railroad activity.
4.2 Locomotive Design Characteristics Pertinent to the Study
Diesel locomotives incorporate some design features which
are somewhat different to those found in other ground
transportation engines. The design features of specific
interest in this study are: 1) the design of the engine
cooling systems, and 2) the method of controlling engine power.
The first design feature which is of interest in this
study is the procedure used in controlling engine coolant
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PENNSYLVANIA
*
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Railroad Routes
- Railroad Traffic
Density Tonnage
Class
Figure 1
Philadelphia AQCR
Tonnage
Class
1
2
3
A
5
6
7
Millions of
Gross ton-miles
per mile of Track
0-0.99
1-4.99
5-9.99
10-19.99
20-29.99
30-39.99
40 and over
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Millions of
Gross coo-nllci
ier mile of Track
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Chicago AQCR
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Railroad Boutas
Railroad Traffic
Density Tonnagi
Millions of
Gross con-tailes
per mile of Trac
0-0.99
1-4.99
5-9.99
10-19.99
20-29.99
30-39.99
and over
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Figure 3
Central Chicago
-------
Railroad Routes
Railroad Traffic
Density Tonnage
Class
Millions of
Gross ton-miles
per mile of Track
0-0.99
1-4.99
5-9.99
10-19.99
20-29.99
30-39.99
40 and over
Figure 4
St. Louis AQCR
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KANSAS
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Density Tonnage
Class
Millions of
Tonnage Gross ton-miles
Class per mile of Track
1 0-0.99
2 1-4.99
3 5-9.99
4 10-19.99
5- 20-29.99
6 30-39.99
7 40 and over
Figure 5
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Legend
Tonnage
Class
Railroad Routes
Railroad Traffic
Density Tonnage
Class
Millions of
Gross ton-miles
per mile of Track
0-0.99
1-4.99
5-9.99
10-19.99
20-29.99
30-39.99
40 and over
(b
J 10 10
Figure 6
Los Angeles AQCR
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Legend
HI lea
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Millions ol
Gross con~miles
per mile of Track
0-0.99
1-4.99
5-9.99
10-19.99
20-29.99
30-39.99
40 and over
PACIFIC UCliAN
Figure 7
Central Los Angeles
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temperature. Normal practice for the control of coolant
temperature and, therefore, engine temperature in road vehicles
is to thermally separate the coolant into two parts. These two
parts or volumes of coolant are located in the engine and in
the radiator and are thermally separated by the thermostat.
Coolant temperature in the engine and the resulting engine
temperature is controlled by the thermostat which regulates the
flow of coolant to the radiator. Use of this design approach
results in: 1) rapid engine warm-up following a cold start
because only a fraction of the coolant in the engine is warmed
during engine warm-up, 2) relatively constant coolant
temperature and as a result relatively constant engine
temperature is maintained as changes in engine load occur, and
3) relatively constant coolant temperature and engine
temperature is maintained versus changes in ambient
temperature. This approach to the design of engine cooling
systems requires the use of an antifreeze to prevent freezing
of the coolant in the engine and the radiator during shutdown,
and in the radiator when the vehicle is operated in low ambient
temperatures.
Normal practice in locomotive design is to treat all of
the coolant as a single volume and to control coolant
temperature by limiting the capability for heat rejection at
the radiator. Two approaches are used on locomotives to limit
the ability of the radiator to reject heat. One approach is to
control the amount of air flowing across the radiator by use of
a variable speed fan drive and shutters while keeping the
radiator full of coolant. The other approach is to store that
part of the coolant which is not in the engine in a large
reservoir and to divert coolant to the radiator as necessary
for temperature control, i.e., little or no coolant is normally
found in the radiator. This second approach to temperature
control of locomotive engines is normally referred to as the
dry radiator method. On some newer locomotives where the dry
radiator method of control is utilized, air flow across the
radiator is also controlled by use of a variable-speed fan.
Many older, dry radiator locomotives employ constant-speed fan
drives which require a greater amount of power for their
operation than that required by the variable-speed fans.
As a result of this cooling system design philosophy,
locomotive engines: 1) require an extensive warm-up period
following shutdown because not only must the great mass of the
engine be warmed but all of the coolant must also be warmed, 2)
experience relatively large changes in coolant temperature, and
as a result engine temperature, between idle and full power
operation, and 3) experience relatively large changes in
coolant temperature and engine temperature as a function of
ambient temperature. The effects of the cooling system designs
on locomotive emissions, within railroad yards, have been
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that: 1) exhaust emissions (mass basis) from idling
locomotives constitute a significant fraction of the total
emissions from locomotives, 2) start-up emissions, while the
occurrences are infrequent, are higher than would occur if only
part of the coolant needed to be warmed up, and 3) emissions
levels following a prolonged idle period tend to be high
because of the general cooling of the engine.
The second design feature which is peculiar to railroad
locomotives and which was of interest in this study is the
design and operation of the throttle. Power settings for
railroad engines (throttle position) generally involve eight
discrete positions or notches on the throttle gate in addition
to the idle and dynamic brake positions. Each notch position
is numerically identified, with notch position one being the
lowest, off-idle, power setting and position eight being
maximum power. In the dynamic brake position, the propulsion
system provides a degree of braking. The dynamic brake
position is not usually found on switch engines.
The throttle lever in the cab of the locomotive is usually
connected to the engine by electrical means as opposed to a
mechanical connection. Because of this type of connection,
each notch on the throttle corresponds to a discrete setting on
the fuel delivery system of the engine and there are no engine
power settings which correspond to throttle settings between
any two notch positions. The net effect of this method of
control is that the engines can operate at only eight distinct
power levels, in addition to idle and dynamic brake.
During accelerations, the usual practice for throttle
operation is for single notch, stepwise increases in power as
opposed to a sweeping change to the highest notch position
which will ultimately be employed.
4.3 Locomotive Duty Cycles
The pattern of operation followed by a piece of equipment,
expressed in terms such a percent of time at a defined load,
speed or other readily identifiable parameter, is usually
referred to as the duty cycle for that piece of equipment. The
combination of the design of the throttle control and the usual
method of operation has permitted locomotive manufacturers and
the railroads to establish historical operating patterns or
duty cycles for locomotives based upon throttle notch
position. This information was of assistance in estimating the
emission contributions of railroads within Air Quality Control
Regions. Substantial increases in the cost of fuel over the
past several years has caused railroads to seek procedures for
conserving fuel. One of the procedures which has been
introduced is a reduction in the time that locomotives spend at
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idle. Precise identification of the amount of change which has
occurred was not possible, however, because of the lack of
recent data on the duty cycle. Historical operating patterns
were, therefore, used as the basis in this study.
The locomotive duty cycle describes the amount of time
spent in each of the throttle notch positions when a locomotive
is available for service. As such, the distribution not only
accounts for the time a unit spends engaged in moving freight,
but also the time spent at idle, either incurred while the
locomotive is awaiting assignment and is not yet an integral
part of a train or is part of a train which is stationary.
Time during which the locomotive is unavailable for service
resulting from factors such as the need for a major overhaul,
scheduled maintenance, or inspections would be excluded from
the daily duty cycle. Data were not available on the amount of
time that locomotives are not available for service. In this
analysis it is assumed that on an annual basis, locomotives are
unavailable for service for approximately 5 percent of the
total time in each year. Expressed as the number of days in
which locomotives are not available for service, this 5 percent
factor corresponds to 20 days per year. On an annual basis
each locomotive is assumed, therefore, to be in service for 345
days.
Within the generic definition of duty cycle, there are two
distinct classes of locomotive duty cycle. The classes apply:
1) to line-haul locomotives, and 2) to switch and transfer
locomotives. Switch and transfer locomotives generally operate
within localized areas and their duty cycles are, therefore,
directly applicable within Air Quality Control Regions.
Line-haul locomotives cross AQCR boundaries and pose problems,
therefore, with respect to the determination of their emissions
within an AQCR.*
In an attempt to define the most representative duty cycle
for each type of locomotive within each AQCR, historical
throttle clock data from the locomotive manufacturers were
reviewed. The information available was not adequate to depict
The horsepower ratings of locomotives range from a high of
about 5,000 hp to under 1,000 hp. The higher power
locomotives are usually used for line-haul purposes with
the smaller locomotives used in switch and transfer
operations. There is no firm rule for distinguishing
between the two types of service with respect to the power
rating of locomotives. For purposes of this study, all
locomotives of 1,500 hp and less were treated as switch
and transfer units with the remainder of the locomotives
classed as line-haul.
-------
-19-
individual regional differences. It is reasonable, however, to
expect that the line-haul locomotives of western railroads
could spend more time in throttle notch eight (full power) and
in dynamic brake (descending long mountain grades) than do
their eastern counterparts. This expectation is based on the
more mountainous terrain found in the western areas of the
country which could entail the extensive use of maximum power
when climbing grades and dynamic brake when descending grades.
Since duty cycles for each region could not be formulated, it
was decided to use the existing industry duty cycles with some
modifications where appropriate.
4.3.1 Switch and Transfer Locomotive Duty Cycle
Generally, switch locomotives operate within a switchyard
or terminal area, while transfer locomotives move rail cars
between switchyards and are involved in branchline service
where rail cars are delivered to or received from customers.
Switch and transfer locomotives are typically smaller, lower
power units.
The literature contains two duty cycles for switch
locomotives (Table 1) . The literature does not contain any
duty cycles for transfer locomotives. It was not possible,
therefore, to distinguish between duty cycles for switch and
transfer locomotives. It was assumed that locomotives employed
in transfer service experience the same duty cycle as those
employed in switch service and a single duty cycle was used for
these two types of service. As shown in Table 1, the two
switch locomotive duty cycles are nearly identical. Dynamic
brake is not included in these cycles because switch
locomotives are not usually equipped with this feature.* The
Atchinson, Topeka, and Santa Fe Railroad cycle (ATSF) was
apparently based on only that railroad's operating experience.
The Electromotive Division of General Motors (EMD) cycle was
chosen to be more representative of national operations since
it seems likely that it was generated from throttle clock data
recorded from several railroads. The duty cycle for switch and
transfer locomotives represents operation on a 24 hour per day
basis for each day of the year that the locomotive is in
service.
During dynamic brake operation, the function of the
locomotive powerplant (engine, generator and traction
motors) is reversed and the powerplant serves as a brake.
-------
-20-
Table 1
Switch Locomotive Duty Cycles
Percent of Time
in Each Notch,
Per 24-Hour Day
Throttle
Notch Position ATSFl/ EMDl/
Engine Off 0 0
Idle 77 77
Notch 1 10 7
Notch 2 57
Notch 3 44
Notch 4 22
Notch 5 11
Notch 6 1 0.5
Notch 7 0 0.5
Notch 8 01
I/ ATSF - Atchinson, Topeka and Santa Fe.
EMD - Electromotive Division, General Motors.
-------
-21-
4.3.2 Line-Haul Locomotive Duty Cycle
Duty cycles which have been developed by the railroad
industry and by locomotive manufactures for line-haul
locomotives are shown in Table 2. The EMD heavy-duty cycle,
the General Electric (GE) maximum cycle and the Association of
American Railroads (AAR) duty cycles may be most representative
of locomotive operation between cities or western railroad
service in general. The EMD medium-duty cycle and the GE
average duty cycles are probably most typical of overall
line-haul freight operations on a national basis.
Since the throttle notch data upon which these cycles are
based were derived from a combination of intercity and
intracity operations, the data would not be expected to
precisely define operations within the metropolitan/suburban
AQCRs under study. It was concluded, therefore, that the
industry duty cycles having high percentages of throttle notch
eight operation were inappropriate for use within AQCRs. Two
reasons predominate in arriving at this conclusion. The first
reason is the lower average speed of trains when operating in
the metropolitan regions as compared to the long intercity
distances where higher speeds are maintained. Operation of the
locomotive in the highest power settings (notches seven and
eight) would, therefore, tend to be emphasized during intercity
operation. Second, although trains are accelerating as they
leave the switchyards or other congested areas, and as a result
require the use of relatively high power settings, it is not
normal operating practice to "sweep" the throttle from a low
notch position to notch seven or eight. Each higher notch
position of the throttle is not normally selected until a
significant portion of the ultimate power in the preceding
notch has been achieved. Because accelerations are
accomplished with an orderly and gradual progression to higher
notch positions, a relatively small amount of time is
accumulated in the highest notches. At reduced speeds, dynamic
brake becomes inefficient and its excessive use could damage
the traction motor of the locomotive because of poor heat
transfer characteristics. The percentage of time spent in
dynamic braking within an AQCR is, therefore, expected to be
less than that which exists for the overall operation of
line-haul locomotives.
On this basis, EPA selected the General Electric
minimum-duty cycle for line-haul locomotives as the basis for
representative operation within an AQCR (Table 3). The values
selected for the percentage of time spent in each notch were
rounded to whole numbers so as to avoid the appearance of great
accuracy. In applying the duty cycle selected for line-haul
locomotive operation in an AQCR, it was assumed that 50 percent
of the total line-haul locomotive operational time was spent
within AQCRs and the other 50 percent was spent in rural
-------
-22-
Table 2
Line-Haul Locomotive Duty Cycles
Throttle
Percent of Time in Each Notch Per 24-Hour
Notch
Position GE^/Min.
Engine Off
Idle
Notch 1
Notch 2
Notch 3
Notch 4
Notch 5
Notch 6
Notch 7
Notch 8
Dyn. Brake
0
59
6
6
6
6
2
2
2
5
1
.0
.5
.5
.5
.5
.9
.9
.5
.2
.5
GE Max.
0
40
2
2
2
2
1
1
1
38
7
.0
.5
.5
.5
.1
.7
.7
.8
.0
.0
GE Avg . 1
0
54
5
2
2
5
2
2
2
21
4
.0
.0
.5
.0
.0
.0
.0
.5
.0
.0
EMD
GE Avg. 2 Heavy!7
0
53.
5.
3.
3.
3.
2.
3.
2.
17.
5.
0
1
9
4
3
8
4
6
0
5
0
41
3
3
3
3
3
3
3
30
8
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
Day
EMD
Med.
0
46
4
4
4
4
4
4
4
17
9
AAR!X
0
43.0
3.0
3.0
3.0
3.0
3.0
3.0
3.0
28.0
8.0
I/ AAR - Association of American Railroads.
GE - General Electric.
EMD - Electromotive Division, General Motors.
-------
-23-
Table 3
Line-Haul Locomotive Duty Cycle Applicable to
Operation Within Air Quality Control Regions
Percent of Time
Throttle in Each Notch,
Notch Position Per 12-Hour Day
Engine Off 0
Idle 59
Notch 1 7
Notch 2 6
Notch 3 6
Notch 4 6
Notch 5 3
Notch 6 3
Notch 7 3
Notch 8 5
Dyn. Brake 2
-------
-24-
areas. The duty cycle for rural line-haul locomotive operation
was calculated* (Table 4) and compared to the maximum-duty
cycles as a check of the assumptions which had been made.
Because of the similarity between the calculated rural-duty
cycle and the AAR, EMD heavy-duty and GE maximum-duty cycles,
it was concluded that the assumptions were reasonable.
4.3.3 Secondary Power Source Duty Cycle
The third duty cycle used in this study was that of the
relatively small diesel engines used to operate the
refrigeration systems of refrigerated rail cars. This group of
engines constitute the secondary power sources which are found
on trains.
The duty cycle for these engines was obtained from Pacific
Fruit Express (PFE 1978). This cycle (Table 5) is based on
transcontinental shipments lasting approximately ten days. The
cargo in this instance is not pre-cooled; hence, the cycle is
more rigorous than if pre-cooled or pre-frozen food was to be
transported. For the purposes of this analysis, the duty cycle
is assumed to occur over a 24 hour period for each refrigerated
rail car that is in service in an AQCR.
Difference between time spent in a throttle notch position
in medium duty cycle on a 24 hour basis and time spent in
the same throttle notch position in minimum duty cycle on
a 12 hour basis gives the time spent in the same throttle
notch position in the calculated rural duty cycle on a 12
hour basis.
-------
-25-
Table 4
Line-Haul Locomotive Duty Cycles Overall
Average, Within AQCRs and In Rural Areas
Throttle
Position
Engine Off
Idle
Notch l
Notch 2
Notch 3
Notch 4
Notch 5
Notch 6
Notch 7
Notch 8
Dynamic
Brake
Overall
Averaqel/
0
51
5
4
3
4
3
3
3
18
Within
AQCR2/
0
59
7
6
6
6
3
3
3
5
In Rural
Areas!/
0
43
3
2
0
2
3
3
3
31
62 10
I/ Average of two G.E. average cycles and EMD medium
applicable to total time; i.e., 24 hours per day.
2/ Based on G.E. minimum cycles and applicable to 01
total time, i.e.,12 hours per day.
3/ Based on difference between hours spent in each notch of the
overall average and within AQCRs cycles.
-------
-26-
Mode
Table 5
Refrigerated Rail Car
Duty Cycle and Engine Loading
Percentage of Engine
Maximum Cool
High Speed Cool
Low Speed Cool
Low Speed -
No Cooling
Time in Mode Speed (rpm)
10 1,200
10 1,200
50 800
30 800
Rated Power
Percent
of Rated
@ Speed Power @ Speed
33 @ 1,200 95% <§ 1,200
33 @ 1,200 72% @ 1,200
20 <§ 800 67% @ 800
20 @ 800 20% @ 800
-------
-27-
5.0 RAILROAD EMISSION ESTIMATES
Three parameters were used in the development of the
estimates of railroad exhaust emissions within the five Air
Quality Control Regions which were studied. The parameters
used were: 1) the locomotive and refrigerated rail car duty
cycles previously developed, 2) exhaust emissions from
locomotives and refrigerated rail car engines, and 3) the
number of locomotives and refrigerated rail cars in use in each
Air Quality Control Region.
5.1 Locomotive Exhaust Emissions
Three sets of data on locomotive emissions were utilized
in developing estimates of individual source exhaust
emissions. Southwest Research Institute (SwRI) tested three
locomotives as part of Contract Number EHS 70-108 for the
Environmental Protection Agency.[1] This work was performed in
1971-72. The locomotives tested were in-use units obtained
from Southern Pacific and included a 1200 hp EMD switch engine,
a 3000 hp EMD line-haul engine and 3600 hp GE line-haul engine.
The second set of data on locomotive emissions was
furnished by EMD. This data set consisted of data taken from
new locomotives in 1978. The data were presented as mean
results from nine 1500 hp engines, eighteen 2000 hp engines and
twenty-two 3000 hp engines. The standard deviations of the
data were also presented. The third and largest set of data
was provided by the Association of American Railroads (AAR).
This data set was collected by AAR between 1981 and 1983. The
data were presented as the means and standard deviations for
each of the groups of engines tested. In total, fifty seven
in-use locomotives were tested. On a manufacturer basis, the
locomotives tested were as follows: EMD; sixteen 2000 hp
engines, two 2250 hp engines, four 2500 hp engines, fifteen
3000 hp engines and eight 3600 hp engines; G.E; five 3000 hp
engines and seven 3600 hp engines. Within this data set the
engines tested were divided into two groups. One group
consisted of engines which were tested immediately after a
major overhaul. The other group consisted of engines which
were tested just prior to the performance of a major overhaul.
In utilizing this data (AAR data) EPA treated the data
collected from engines immediately after a major overhaul as
being eguivalent to new locomotive data.
The estimates of in-use locomotive emissions were
developed from the three data sets as follows. In the first
step, the emission data on each engine type (e.g., the 3000 hp
EMD locomotive) from each source were inspected to determine
whether the data were similar or dissimilar. Since the test
data on each engine tested in each data set were not provided,
-------
-28-
an approximate rather than a statistically precise
determination of similarity or dissimilarity was made. Test
results from the three data sources on locomotives of the same
specification were treated as being similar when the difference
between the mean results was less than the sum of the standard
deviations for the majority of the data on that locomotive
type. Application of this test for similarity or dissimilarity
between data sets resulted in the removal from the data base of
one set of test results on a single locomotive (the 3000 hp EMD
locomotive tested by SwRI in 1971-1972).
The second step in the development of the estimates of
emissions from in-use locomotives was the calculation of "new"
locomotive and "used" locomotive (i.e., locomotives approaching
a major overhaul) emission rates. "New" locomotive emissions
were derived from the data supplied by EMD and from the AAR
data on locomotives immediately following a major overhaul.
"Used" locomotive emissions were derived from the AAR data on
locomotives approaching a major overhaul and from SwRI data.
Since the means of the emission results contained in each data
set were obtained from differing sample sizes, the average
"new" and average "used" emission rates were calculated as
sampling size weighted means; i.e., the sum of the products of
mean sample emissions and sample size was divided by the sum of
the sample sizes to develop the average "new" and average
"used" locomotive emissions. Implicit within this
calculational methodology is the assumption that changes in
locomotive emissions occur linearly with time.
The third step in the development of in-use locomotive
emissions estimates was the calculation of the emissions rates,
for "average" in-use locomotives of the types tested. This
calculation utilized the assumption that there is a linear
change in emission rates as locomotives age from the "new" to
the "used" condition. With this assumption, emissions from an
average locomotive are calculated as the mathematical average
of the new and used values. The emissions rates for average
locomotives of the eight specifications tested are shown in
Tables 6 through 8. Hydrocarbon emissions are shown in Table
6, carbon monoxide emission in Table 7 and oxides of nitrogen
emission are shown in Table 8. The units employed are grams of
pollutant per hour of operation in each throttle notch position.
The fourth step in the procedure was the calculation of
the in-use weighted average emissions for line-haul and for
switch and transfer locomotives. Since there are a greater
number of horsepower ratings for in-use locomotives than there
are power ratings in the data base, a degree of grouping of the
in-use locomotives was necessary. The in-use locomotives were
grouped so that the ratings of the test locomotives were equal
to the power ratings of the greater number of in-use
-------
Table 6
Average Locomotive Hydrocarbon Emissions by Throttle Setting
Locomotive Emissions (g/hr)
Throttle
Notch
Idle
1
2
3
4
5
6
7
8
Dyn Brake
EMD.?/
3600 hp
251
193
200
259
306
422
529
767
971
363
GE?/
3600 hp
835
822
4,511
9,728
7,922
8,781
8,786
8,840
10,044
1,941
EMD3/
3000 hp
228
201
.236
316
382
544
728
1,002
1,276
366
GE4/
3000 hp
532
608
1,177
2,220
3,359
3,850
4,029
5,330
6,234
2,271
EMD5/
2250/2500 hp
231
170
180
219
256
339
425
565
806
316
2000 hp
152
146
169
224
304
428
571
789
1,005
252
EMDZ/
1500 hp
97
93
116
145
193
271
367
517
660
1000 hp
387
452
638
984
1,482
1,830
2,387
2,960
3,976
Data Source, time frame of testing, number of engines tested
I/ AAR, 1981-1983, 9 engines.
2/ AAR, 1981-1983, 3 engines; SwRI, 1971-1972, 1 engine.
3/ AAR, 1981-1983, 12 engines; EMD, 1978, 22 engines.
4/ AAR, 1981-1983, 7 engines.
5/ AAR, 1981-1983, 6 engines.
6/ AAR, 1981-1983, 16 engines; EMD, 1978, 18 engines.
7/ EMD, 1978, 9 engines.
8/ SwRI, 1971-1972, 1 engine.
VD
I
-------
Table 7
Average Locomotive Carbon Monoxide Emissions by Throttle Setting
Locomotive Emissions (g/hr)
Throttle
Notch
Idle
1
2
3
4
5
6
7
8
Dyn Brake
EMD.?/
3600 hp
588
432
484
610
720
1,033
2,480
3,849
4,472
818
GE2-/
3600 hp
481
658
1,588
2,325
3,036
3,721
4,466
4,454
5,099
2,352
EMD!/
3000 hp
566
392
362
466
570
1,160
2,591
5,036
6,092
840
GEi/
3000 hp
1,048
962
2,236
3,858
7,964
8,504
12,038
8,339
7,892
2,780
2250/2500 hp
599
316
304
378
448
832
2,122
5,060
9,868
635
2000 hp
291
208
350
441
458
616
1,120
2,686
5,704
702
EMD!/
1500 hp
174
184
295
337
351
416
659
1,959
5,305
EMD8-/
1000 hp
160
273
341
481
560
702
768
1,052
1,844
Data Source, time frame of testing, number of engines tested
I/ AAR, 1981-1983, 9 engines.
2/ AAR, 1981-1983, 3 engines; SwRI, 1971-1972, 1 engine.
3/ AAR, 1981-1983, 12 engines; HMD, 1978, 22 engines.
4/ AAR, 1981-1983, 7 engines.
5/ AAR, 198171983, 6 engines.
6/ AAR, 1981-1983, 16 engines, EMD, 1978, 18 engines.
7/ EMD, 1978, 9 engines.
8/ SwRI, 1971-1972, 1 engine.
o
I
-------
Table 8
Average Locomotive Oxide of Nitrogen Emissions by Throttle Setting
Locomotive Emissions (g/hr)
Throttle
Notch
Idle
1
2
3
4
5
6
7
8
Dyn Brake
EMD!/
3600 hp
1,561
2,331
3,534
5,852 .
8,685
11,808
15,436
24,774
29,809
3,540
GE2/
3600 hp
978
4,083
11,880
14,944
19,343
23,427
28,061
28,666
33,050
5,043
EMD^/
3000 hp
1,448
3,105
5,367
9,091
13,282
18,626
23,337
30,344
36,409
1,771
GE*'
3000 hp
977
2,009
5,023
13,120
17,871
25,023
29,354
34,262
42,750
5,798
EMD5-/
2250/2500 hp
1,434
1,765
3,163
4,794
6,773
9,306
11,879
15,287
23,859
2,486
EMD§/
2000 hp
1,059
1,506
3,461
6,497
10,648
15,617
21,054
27,112
31,388
3,255
EM)!/
1500 hp
957
1,248
2,763
5,605
9,598
13,932
17,743
21,623
23,864
-
EMD**/
1000 hp
335
626
920
2,003
3,218
4,946
6,718
8,367
10,220
-
Data Source; time frame of testing, number of engines tested
I/ AAR, 1981-1983, 9 engines.
2/ AAR, 1981-1983, 3 engines; SwRI, 1971-1972, 1 engine.
3/ AAR, 1981-1983, 12 engines; EMD, 1978, 22 engines.
4/ AAR, 1981-1983, 7 engines.
5/ AAR, 1981-1983, 6 engines.
6/ AAR, 1981-1983, 16 engines, EMD, 1978, 18 engines.
7/ EMD, 1978, 9 engines.
8/ SwRI, 1971-1972, 1 engine.
i
CO
-------
-32-
locomotives in each in-use group. The horsepower groupings of
in-use locomotives, the number of in-use locomotives in each
group and the horsepower ratings of the test-engines used to
represent the in-use groups are shown in Table 9.
The calculation of the in-use weighted emissions averages
was performed by summing the products of the emission rates for
the test engines and the number of in-use engines in the group
so represented and dividing by the total number of in-use
locomotives in the group. The results of these calculations
are shown in Table 10 for line-haul locomotives and in Table 11
for switch and transfer locomotives.
The fifth and final step in the procedure was the
calculation of locomotive emissions in each AQCR under study.
This step was performed by determining the daily emissions of
"average" line-haul and switch and transfer locomotives when in
an AQCR and multiplying by the number of locomotives of each
type in the AQCR and the number of days per year that each
locomotive is in service (i.e., 345 days).
The procedures used for developing the duty cycles were
described in the Background section of this report. These duty
cycles were employed in this calculation.
The daily (i.e., duty cycle weighted) locomotive emissions
were calculated by determining the product of the emissions in
each throttle notch and the number of hours spent in each
throttle notch position and summing the values so calculated.
The results of these calculations are shown in Tables 12 and
13. As can be seen from these tables, an average line-haul
locomotive emits on a daily average basis 14.43 Ib. of HC,
31.03 Ib. of CO and 160.49 Ib. of NOx, while an average switch
and transfer locomotive emits 15.28 Ib., 13.58 Ib. and 77.66
Ib. of HC, CO, and NOx respectively.
Estimation of the number of locomotives in each AQCR was
performed by extrapolating from information supplied by the
Federal Railroad Administration (FRA). For the 1978-1979
timeframe, FRA safety inspectors provided EPA with data on the
number of switch and transfer locomotives in the AQCRs being
studied. This information was used to extrapolate to the total
number of locomotives in an AQCR by assuming that there is a
direct relationship between the number of switch and transfer
locomotives in a region and the number of line-haul locomotives
serving that region. The assumption is that the fraction of
the total number of line-haul locomotives serving any region is
the same as the fraction of the total number of switch and
transfer locomotives operating in that region. The rationale
leading to this assumption is that there should be a relatively
fixed relationship between the number of line-haul locomotives
-------
Table 9
In-Use Locomotive Power Rating Groups, Number of Locomotives
by Groups, and Test Engines Representing In-Use Groups
Locomotive groupings by power level
Line-Haul
In-Use
Horsepower
Group
Number of
Locomotives
in group
Test Engine
Power Rating
EMD
3300 hp
& Over
1,753
EMD
3,600 hp
GE
3200 hp
& Over
655
GE
3,600 hp
EMD
3200 thru
2800 hp
5,818
EMD
3,000 hp
GE
3000 thru
1800 hp
2,386
GE
3,000 hp
EMD
2700 thru
2250 hp
2,402
EMD
2,500 and
2,250 hp
EMD
2000 thru
1600 hp
6,192
EMD
2,000 hp
Switch and Transfer'
EMD
1500 thru
1300 hp
2,807
EMD
1,500 hp
EMD 1200 hp & under
GE 1000 hp &
2,003 EMD
72 GE
EMD
1,200 hp
under
u>
Co
-------
-34-
Table 10
In-Use Weighted Average Line-Haul
Locomotive Emissions By Throttle Position
Throttle Emissions (gm/hr per locomotive)
Position HC CO NOx
Idle 264 540 1,257
1 250 407 2,248
2 467 637 4,489
3 827 945 8,121
4 961 1,535 11,976
5 1,161 1,932 16,826
6 1,306 3,286 21,355
7 1,662 7 4,564 27,340
8 2,017 6,481 33,291
Dynamic 613 1,060 3,112
Brake
Table 11
In-Use Weighted Average Switch and Transfer
Locomotive Emissions By Throttle Position
Throttle Emissions (gm/hr per locomotive)
Position HC CO NOx
Idle 220 168 692
1 246 222 983
2 338 315 1,979
3 502 398 4,073
4 741 440 6,884
5 934 538 10,110
6 1,226 705 13,053
7 1,556 1,573 15,984
8 2,071 3,833 18,060
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-35-
Table 12
Line-Haul Locomotive Emissions
Per Locomotive, Per 12-Hour Day in an AQCR
Throttle Duty
Position Cycle
Idle 59
1 7
2 6
3 6
4 6
5 3
6 3
7 3
8 5
Dynamic Brake 2
Total 100
Operating
Hours
7.08
0.84
0.72
0.72
0.72
0.36
0.36
0.36
0.60
0.24
12.00
Emissions (pounds/day)
HC CO NOx
4.12
0.46
0.74
1.31
1.53
0.92
1
1
04
32
2.67
0.32
8.44
0.75
1.01
1.50
2.44
1.53
2.61
3.62
8.57
0.56
14.43 31.03
19.61
4.16
7.13
12.89
19.01
13.35
16.95
21.70
44.04
1.65
160.49
Table 13
Switch and Transfer Locomotive
Emissions Per Locomotive, 24-Hours Per Day
Throttle
Position
Idle
1
2
3
4
5
6
7
8
77
7
7
4
2
1
0.5
0.5
1
Operating
Hours
18.48
1.68
1.68
0.96
0.48
0.24
0.12
0.12
0.24
Emissions (pounds/day)
HC CO NOx
1
1
8.96
0.91
25
06
0.78
0.49
0.32
0.41
1.10
6.85
0.82
1.67
0.84
0.47
0.29
0.19
0.42
2.03
Total
100
24.00
15.28 13.58
77.66
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which service an area and the number of switch and transfer
locomotives which service the line-haul locomotives, because
switch and transfer locomotives are used to process the freight
cars which enter and leave a region (freightyard, for
example). The numerical values for these distributions,
adjusted to the number of locomotives in service in 1984,[2]
are given in Table 14.
Line-haul and switch and transfer locomotive emissions for
each AQCR, expressed as tons per year, are shown in Table 15.
5.2 Secondary Power Sources Exhaust Emissions
Emissions from refrigerated rail cars (secondary power
sources) were calculated as described below and the resulting
contributions in each AQCR are shown in the railroad emissions
summary table.
Two basic types of refrigerated rail car are currently in
service throughout the nation. These types are nonmechanical
and mechanical refrigerated rail cars. Nonmechanical units
utilize either block ice, a mixture of crushed ice and salt, or
solid carbon dioxide (dry ice) as the cooling medium.
Mechanical units are powered by an internal combustion engine.
In this analysis, only mechanical refrigerated units were
considered since only these units have exhaust emissions while
in the railroad system.
Mechanical refrigeration units use a relatively small
diesel engine to generate electric power which operates the
refrigeration system. In addition, most cars are equipped with
an electrical heating system. This system is used to defrost
the car's interior or, in winter, to protect perishables from
freezing temperatures. Consequently, most refrigerated cars
are capable of maintaining internal temperatures of from -20°F
to +70°F and may be operated throughout the year. These cars
are also used without their mechanical refrigeration devices in
operation when nonperishable commodities do not require
protection from temperature extremes.
A review of alternative methods for quantifying the number
of refrigerated cars in each AQCR concluded that the most
accurate assessment could be made by basing refrigerated car
population estimates on actual in-use data obtained from the
analysis of rail operations being conducted by the Chicago
Terminal Project. This project was jointly funded by the
Federal Railroad Administration and the Association of American
Railroads. EPA was not, however, able to secure the desired
data from this source and had to adopt an alternative method.
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Table 14
Number of Locomotives in Each AQCR
AQCR
Philadelphia
Chicago
St. Louis
Kansas City
Los Angeles
Switch and
Transfer Locomotives
Percentage Number
of Total1/ of Unitsi/
1.62
13.13
2.06
2.25
1.99
79
641
101
110
97
Line-Haul Locomotives
Percentage Number
of Total of Units3/
1.62
13.13
2.06
2.25
1.99
311
2,522
396
432
382
I/ Percentage of total switch and transfer locomotives derived
from count of switch and transfer locomotives in service in
each city as furnished by Federal Railroad Administration in
1979, divided by total number of switch and transfer
locomotives in service in 1979.
2/ Number of switch and transfer locomotives in each AQCR
derived from the percentage of the total number of switch and
transfer locomotives and the total number in service in 1984.
3/ Number of line-haul locomotives in each AQCR derived from the
percentage of the total number of switch and transfer
locomotives and the total number of line-haul locomotives in
service in 1984.
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Table 15
Line-Haul and Switch and Transfer Locomotive
Emissions in Five AQCRs
Emissions (tons/year)
AQCR HC CO NOx
Philadelphia:
Line Haul 774 1,665 8,610
Switch 208 185 1,058
Chicago:
Line Haul 6,278 13,499 69,820
Switch 1,690 1,502 8,587
St. Louis:
Line Haul 986 2,120 10,963
Switch 266 237 1,354
Kansas City:
Line Haul 1,075 2,312 11,960
Switch 290 258 1,473
Los Angeles:
Line Haul 951 2,045 10,575
Switch 256 227 1,300
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Refrigerated car activity was approximated by weighting
the national-population of these units by the amount of traffic
in each region (Table 16). This method assumes that
refrigerated units are equally distributed throughout the
nation based on the amount of freight moved in each area. This
may underestimate refrigerated car operations in large market
areas and rail terminals which, because of high demand and
longer car residence times, would tend to agglomerate larger
concentrations of these units, e.g., Philadelphia, Chicago, St.
Louis, and Kansas City. The possibility of overestimation
exists in smaller markets and producing areas, e.g., the Los
Angeles region. However, the existence of a major port
facility in Los Angeles may moderate this effect.
The literature contains inconsistent population estimates
of the nation's mechanical refrigerator cars. A statistical
summary for the years 1966-76 published by the AAR (1977),
reported 9,259 mechanical and 3,613 nonmechanical units in
1976. This compares favorably with rail statistics published
by the Interstate Commerce Commission (ICC 1976). Both sources
are based on ICC annual reports, which are submitted by each
Class I railroad (railroads are grouped into classes, with
Class I railroads being the largest). In the Yearbook of
Railroad Facts (AAR 1977), the total for all refrigerated cars
owned by Class I railroads is given as 74,936. The difference
between the two AAR documents for refrigerated cars is
approximately 62,000 units. Moreover, the figures from AAR's
statistical summary (AAR 1977) are internally inconsistent. In
1967, the total refrigerated car population was reported to be
49,399, but one year later in 1968 the total population was
reported as 15,638.
To determine the exact number of refrigerated cars in the
nation, the AAR Car Service Division was contacted (AAR 1978).
According to the CS-8A report from the Train II system, 30,106
diesel-electric refrigerator cars were in service as of January
1, 1977. This information is reported directly from the car
owners to the AAR. Therefore, this figure represents the 1976
national fleet of these cars owned by Class I and II railroads
(large railroads) as well as other companies and shippers and
was used by the EPA in the estimation of emissions from
secondary power sources.
Table 16 shows the average number of refrigeration units
which reside in each region at any one time. As a worst case
condition, it is assumed that each of the diesel-electric units
is in operation 24 hours a day. The same number of days per
year wherein the units are actually in service was assumed for
refrigerated cars as had been used for locomotives.
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Table 16
Refrigerated Rail Cars in Each AQCR
AQCR
Percent Traffic
(AQCR to Total)
Total Diesel-
Electric Units!/
Regional
Diesel-
Electric Units
Philadelphia
Chicago
St. Louis
Kansas City
Los Angeles
0.57
2.26
1.11
0.68
0.84
30,106
30,106
30,106
30,106
30,106
172
680
334
205
253
I/ AAR (1978).
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Mechanical refrigeration units typically use the Detroit
Diesel-Allison 2-71 engine. This 2-stroke, 2-cylinder diesel
engine is nominally rated for 68 horsepower at 2,000 rpm. The
EPA has no exhaust emission data on the Detroit Diesel-Allison
2-71 engine. Emission tests on a similarly configured engine
from the same manufacturer have, however, been made. Emission
rates for this engine, the Detroit Diesel-Allison 6V-71, were
determined by the Southwest Research Institute (Hare and
Springer 1973). Because this engine, the 6V-71, is essentially
three 2-71 engines mounted on a common crankshaft, the
mechanical refrigerated car emission rates (Table 17) for each
of the modes of operation in the duty cycles were developed by
dividing the data on the 6V-71 engine by a factor of three.
The daily duty-cycle weighted emissions presented in Table 18
for refrigerated car engines were derived from this source.
Combining the refrigerated car daily emissions, the number of
refrigerated cars per AQCR and the number of days per year in
which the refrigerated cars are in service resulted in the
annual emissions contributions of the secondary power sources.
These values, expressed as tons per year are shown in Table 19
and constitute the final component of railroad emissions in
each AQCR.
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Table 17
Refrigerated Rail Car Emissions by Power Settingl/
Percent of Rated Emissions (q/hour)
Power @ Speed HC CO NOx
95% <§ 1200 rpm 14 1200 650
72% @ 1200 rpm 13 30 680
67% @ 800 rpm 10 30 580
20% @ 800 rpm 7 20 200
I/ Extrapolated from data on a Detroit Diesel 6V-71 engine.
"Exhaust Emissions from Uncontrolled Vehicles and Related
Equipment Using Internal Combustion Engines," Hare and
Springer, Southwest Research Institute, 1973.
Table 18
Refrigerated Rail Car Emissions
Emissions (pounds/day per refrigerated rail car)
HC CO NOX
0.52 7.62 25.56
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Table 19
Railroad Emissions in Five AQCRs
Emissions (tons/year)
AQCR HC CO NOx
Philadelphia:
Line Haul 774 1,665 8,610
Switch 208 185 1,058
Secondary Power 15 226 758
Total 997 2,076 10,426
Chicago:
Line Haul 6,278 13,499 69,820
Switch 1,690 1,502 8,587
Secondary Power 61 894 2,998
Total 8,029 15,895 81,405
St. Louis:
Line Haul 986 2,120 10,963
Switch 266 237 1,354
Secondary Power 30 439 1,473
Total 1,282 2,796 13,790
Kansas City:
Line Haul 1,075 2,312 11,960
Switch 290 258 1,473
Secondary Power 18 269 904
Total 1,383 2,839 14,337
Los Angeles:
Line Haul 951 2,045 10,575
Switch 256 227 1,300
Secondary Power 23 333 1,116
Total 1,230 2,605 12,991
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6.0 ENVIRONMENTAL IMPACT OF RAILROAD EMISSIONS
6.1 Non-Exhaust Emissions
6.1.1 Refueling Losses
Historically, fuel spillage and leakage have apparently
been widespread and chronic railroad problems. While the
estimates of fuel losses vary significantly, the estimates
always point to substantial losses. The Stanford Research
Institute (1977) estimated that about 10 percent of the
reported fuel consumption of line-haul locomotives owned by
Class I railroads (the largest railroads) was spilled or
unaccounted for. Individual railroads have reported fuel
spillage and losses to be between 0.1 and 3.0 percent of the
total fuel purchased by Class I railroads (LMOA 1975). Based
on Southwest Research Institute (SwRI) figures, up to 367
million gallons (9 percent of consumption) of diesel fuel or
about 367 million dollars ($l/gal) have been spilled or
unaccounted for each year.
To estimate only the amount of fuel spilled each year
during refueling, a conservative 2 percent (based on the LMOA
reference) of the approximately 4 billion gallons purchased, is
assumed. Based on these figures, a minimum of 80 million
gallons or 80 million dollars worth of fuel at present fuel
prices, is spilled during refueling operations. This
represents about $3,300 worth of fuel for each of the
approximately 24,000 locomotives presently in service.
The causes of fuel losses during refueling operations
appear to be well known. The two primary problems are: 1)
improperly attended manually operated fuel nozzles, and 2) poor
maintenance of equipment. Because of the high delivery rates
during the refueling operation, 200-300 gallons per minute,
even difficulties of short duration can lead to a large volume
spill. Additional losses occur when the locomotive fuel tanks
are filled to excess or "topped off." In many cases, excess
fuel drains from the fill pipe when the cap is not replaced
properly or from the overflow vents when the train accelerates
or rounds a curve.
Many of the accidental spills can be eliminated by the use
of automatic shut-off refueling systems. Although some of
these systems are in-use, many railroads have apparently not
installed them because of high initial costs and increased
maintenance costs relative to those incurred for manual
systems. Apparently, the railroads have, on a historical
basis, not found it cost effective to control the loss of fuel.
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Even though the magnitude of refueling losses is very
large, a preliminary investigation indicated this is not a
significant source of air pollution. The high boiling point of
diesel fuel precludes any large volume of gaseous hydrocarbons
entering the atmosphere from the spilled fuel. The spilled
fuel eventually, however, percolates into the ground. Even if
these HC emissions were a significant contributor to air
pollution, the railroad companies are now, or are expected in
the future, to reduce refueling losses. As part of the Spill
Prevention Control and Countermeasure Plans (SPCCP) mandated by
the Federal Water Pollution Control Act (40 CFR 112), refueling
terminals are being equipped with fuel recovery systems to
prevent these liquid contaminants from reaching navigable
waterways. At the same time, these measures eliminate much of
the potential for fuel evaporation. The fuel recovery systems
consist of concrete and metal drain pans under the rails at
refueling points. After collection, the fuel is sent to a
waste water treatment facility or is reused in a variety of
ways, including use as a power plant or locomotive fuel. The
economical reuse of this otherwise wasted resource helps offset
the expenses of the SPCCP system.
The increasing cost of diesel fuel as well as possible
shortages are expected to provide the strongest impetus for the
elimination of refueling and spillage losses. This growing
economic incentive in conjunction with the fact that proven
technology exists for reducing this waste, is making it
increasingly cost effective to install automatic refueling
devices and provide proper maintenance. The cost-saving
potential should be the most effective means of controlling
emissions from this source.
6.2 Exhaust Emissions
6.2.1 Localized Effects
Areas which would typically experience the greatest air
pollutant concentrations and longest exposure times to
locomotive emissions are switch yards and those areas in close
proximity to switchyards with high levels of railroad
activity. The land use adjacent to 1,107 rail yards, or 27
percent of all rail yards, is classified as residential
(FRA/ORD-76/304) .
To assess the potential air quality impact of locomotive
operations on a localized basis, the published literature was
reviewed for information pertaining to this situation. No air
quality monitoring in the vicinity of rail facilities was
found, although analyses of the train crew's working
environment do exist. Unfortunately, the majority of this work
has been confined to determining exposure levels during worst
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case tunnel operations. Only one effort to model the effects
of locomotive railyard operations on ambient air quality was
found. A discussion of the relevant air quality monitoring and
modeling studies follows.
6.2.1.1 Air Quality Monitoring
Two studies report nontunnel "background" concentrations
(Thompson 1973 and Hobbs et al. , 1977). The type of rail
operation represented by Thompson's low exposure level
(background concentration) is undefined in his report and since
it may have been measured during line-haul and not switchyard
service, it is not discussed further.
The analysis of localized, train-generated air
contaminants by Hobbs et al. , (1977) contains data collected in
the cabs of switchyard locomotives. This study is summarized
only to indicate whether the potential problem can be dismissed
or if additional information is necessary. This is, of course,
predicated on the assumption that the locomotive cab
environment, during switchyard operations, represents a worst
case condition because of its proximity to the engine exhaust
and because air contaminants will be diluted to some extent as
they are blown across the boundary of the rail facility.
Therefore, if a problem does not exist in the cab of the
locomotive, it is probable that a problem does not exist in the
vicinity of concentrated rail operations.
Hobbs et al., (1977) continuously monitored the air in the
cabs of three different switchyard locomotives for a total of
approximately 19 hours. The 5-hour time weighted averages for
several pollutants are shown in Table 20. If these data are
regarded as the maximum 8-hour concentration for CO, the
maximum 3-hour concentration for HC, and the annual averages
for particulates and NOx (i.e., the worst possible case), three
pollutants (CO, particulate, and NOx) are below the quality of
the ambient air standards and one (HC) is above. (The HC
standard is not health-based. It was promulgated because
hydrocarbons are precursors to photochemical oxidants.) The
high concentration of HC in the cab could be the result of
contributions from several sources within the locomotive.
Therefore, it may not be representative of the external
environment (i.e., there is probably no relationship to the
NAAQS welfare standard).
Unfortunately, Hobbs et al., (1977) did not include a
discussion of the conditions under which the test values were
recorded. This lack of information makes it difficult to
determine if the locomotives being measured were in a worst,
typical, or even a best case environment. The most important
unknown is the ambient air quality in which the switch units
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Table 20
Summary of Air Contaminant Levels in
the Cab of Long-Hood, Forward Switch Yard Locomotives
NAAQS
Substance
Carbon Monoxide
Particulates
Nitrogen Dioxide
Hydrocarbons
5-Hour Time
Weighted Average
0.26 ppm
10 ug/m3
0 . 03 ppm
3.12 ppm
Health
Effects
9 ppm
75 ug/m3
Welfare
Effects
0.05 ppm
0 . 24 ppm
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were operating, If the ambient air quality had been measured,
a direct analysis of the localized effects could have been
performed.
6.2.1.2 Air Quality Modeling
The impact of diesel locomotive exhaust emissions from an
Amtrak maintenance-of-way (MOW) base was modeled as part of an
environmental impact statement which evaluated the facility's
effect on localized air quality. An MOW base is a facility
from which the right-of-way is maintained. It provides for
employee parking and support facilities, office space, shops,
interior and exterior security storage areas, and an external
storage area for maintenance of equipment. The track area in
the MOW is also used to store idling locomotives when they are
not in-use along the right-of-way.
The ambient air quality modeling in the vicinity of the
MOW was performed by DeLuew, Gather/Parsons and Associates for
the Department of Transportation (DOT). In this analysis,
Hanisch (1978) specifically modeled maximum 1-hour N02
pollutant concentrations only. In the model, it was assumed
that three, 2-cycle, roots-blown, EMD switch locomotives (1,500
hp) were allowed to idle when parked end-to-end in the MOW (a
normal occurrence).
For the worst case meteorological conditions (presumably
the wind was blowing steadily in the direction of the most
sensitive receptor), hourly concentrations of approximately 200
ug/m3 or 0.10 ppm were predicted at about 85 meters (280
feet) downwind. There is, however, no national short-term
N02 standard. EPA has considered the need for such a
standard with consideration given to a maximum hourly N02
concentration of approximately 0.25 ppm. For the worst case
modeled, the hourly N02 concentration was below the level
which was considered by EPA.
6.2.2 Within AQCRs
Table 21 shows the estimated yearly railroad emissions,
the total anthropogenic emissions inventories for 1983 (most
recent year available) and the percentages of the totals
contributed by railroads for the five Air Quality Control
Regions which were studied.
The estimates of railroad contributions to the total
anthropogenic emission inventory vary by AQCR, i.e., the
estimated HC contributions varied from a low of 0.12 percent in
Los Angeles to a high of 1.33 percent in Chicago, CO
contributions varied between 0.06 percent in Los Angeles and
0.53 percent in Kansas City, and NOx contributions varied
-------
Table 21
Railroad Emission, Total Anthropogenic Emissions and
Percentage Contributions by Railroads for Five AQCR's
AQCR
Philadelphia
Chicago
St. Louis
Kansas City
Los Angeles
Emissions (1000 tons/year)
HC
Railroad Total %
1.00
8.03
1.28
1.38
1.23
429
603
251
128
1,048
.85
.27
.05
.21
.14
0.23
1.33
0.50
1.08
0.12
CO
Railroad Total %
2.08
15.90
2.80
2.84
2.61
1,633
2,228
932
532
4,307
.91
.03
.69
.18
.33
0.13
0.07
0.30
0.53
0.06
NOx
Railroad Total %
10.
81.
13.
14.
12.
43
41
79
34
99
292.48
551.07
356.11
162.19
533.98
3.57
14.77
3.87
8.84
2.34
VD
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between 2.34 percent in Los Angeles and 14.77 percent in
Chicago. The estimates suggest that railroads should be viewed
as significant sources of NOx emissions in some AQCRs, HC
emissions may be significant in some AQCRs while, along with
CO, may be of little significance in other AQCRs.
Inspection of Tables 12 and 13 on the basis of locomotive
throttle notch position, shows that the idle mode tended to be
the single largest contributor of railroad hydrocarbon and
carbon monoxide emissions. For switch and transfer locomotives
the idle mode was also the largest contributor of NOx
emissions. For line-haul locomotives, the idle mode was the
third largest contributor of NOx emissions. After the idle
mode, notch 8 tended to be the second major contributor of
locomotive emissions. To place these observations in
perspective, the individual percentile contributions of these
operational modes were calculated and are presented in Table
22. The largest contribution to NOx emissions came from notch
8 operations and represented approximately 24 percent of the
total railroad emissions of NOx. Idling locomotives
contributed approximately 14 percent of total railroad NOx
emissions in AQCRs. Idling locomotives were the largest
operational mode contributors of hydrocarbon and carbon
monoxide emissions at approximately 34 percent and 29 percent
respectively. Notch-8 operation was the second largest
contributor of carbon monoxide and hydrocarbon emissions at
approximately 26 percent and 16 percent, respectively.
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Table 22
Percentage of Total Railroad Emissions in AQCRs
Contributed by Idle Mode and Notch-8 Operations!/
Percent of Total Emissions by Mode
Idle Notch-8
HC CO NOx HC CO NOx
Switch and Transfer
Locomotives 12.3 5.0 3.8 1.5 1.5 1.3
Line-Haul Locomotives 22.2 24.4 10.3 14.4 24.8 23.1
Switch and Transfer plus 34.5 29.4 14.1 15.9 26.3 24.4
Line-Haul Locomotives
I/ Calculated from emission rates shown in Tables 12, 13, 14,
and 19.
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7.0 POTENTIAL EMISSION REDUCTION TECHNIQUES
Procedures which have a theoretical potential* for
reducing locomotive gaseous emissions fall into two general
categories. These categories are modifications to the duty
cycle and the application of emission control technology. The
benefits which are projected for these categories are discussed
in this chapter.
Since there was no data in the literature on either direct
measurements of particulate emissions from locomotives or the
effects of particulate control strategies on locomotive
engines, quantification of potential particulate control was
not attempted. Particulate control strategies presently under
development by manufacturers of heavy-duty diesel truck and bus
engines together with a reduction in the sulfur level of
locomotive diesel fuel may, to greater or lesser extents, be
applicable to locomotives.
7.1 Duty Cycle Modifications
7.1.1 Engine Shutdown When Not in Active Service
Historically, diesel locomotives have been allowed to idle
when not in active service. These periods of standby idle are
often extensive; they may routinely be as high as eight or more
hours consecutively, with prolonged periods (48 hours or more)
not being uncommon under certain conditions.
The railroad industry has historically found it more
attractive to allow these diesel engines to idle rather than to
shut them down. An idling locomotive engine is relatively warm
and immediately available for service. When a cold locomotive
engine is started, its large mass (30,000 to 50,000 Ibs)
dictates a lengthy warm-up period before maximum horsepower can
be developed (up to two hours when the engine has completely
cooled to an ambient temperature of 50° to 60°F). During most
of the warm-up period, the locomotive is unavailable for use
and could present a blockage on the section of track where the
warm-up is occurring.
It should be carefully noted that some procedures which
exhibit a theoretical potential for reducing locomotive
emissions may not be practical for use. These procedures
are, however, included in the discussion together with the
factors influencing their impracticality.
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In addition to the lengthy warm-up period required, other
time-consuming and potentially expensive problems have been
associated with starting a cold locomotive diesel engine
(assuming that the ambient temperature is high enough to allow
an engine start to be achieved). These problems are associated
with the size of the engine and, to a certain extent, the
design and maintenance of the engine. Coolant may leak past
the cylinder liner to cylinder head seals into the cylinder(s)
and, if it is not manually purged, could cause a hydraulic lock
in the engine during cranking. This hydraulic lock in
combination with the high inertia of the moving parts of the
engine and the generator rotor will result in severe engine
damage. Leaking of coolant past the cylinder liner to cylinder
block seals would contaminate the engine oil. Contamination of
the engine oil with a relatively large volume of water would
cause bearing failures (leakage of a relatively small volume of
water during engine shut-down can be tolerated because the
water is evaporated when the oil is heated to operating
temperature). During prolonged engine shutdown, lubrication
oil drains back into the oil pan, thereby leaving many engine
components unlubricated at start-up. This temporary oil
starvation at start-up causes excessive wear rates during the
period of inadequate lubrication and, with repeated
occurrences, will result in engine damage. To prevent these
problems, the historical practice has been to have trained
maintenance personnel open cylinder test valves to drain any
coolant from the cylinders, pre-lubricate, and manually turn
the engine one or two revolutions before starting is attempted.
As a means of reducing fuel consumption, manufacturers
have recently shown that many newer locomotives can be shut
down with relative safety when the ambient temperature is 50°F
or above. Protection against damage resulting from a hydraulic
lock is achieved by providing a means whereby an extremely low
cranking speed is used initially. If a hydraulic lock does not
occur, normal cranking speed is then employed to start the
engine. Should a hydraulic lock occur, it is rectified prior
to the use of normal cranking speed by opening the cylinder
test valves and draining the water.
At ambient temperatures below 50°F, starting of these
large diesel engines is very difficult. At temperatures below
35°F starting is usually impossible. This characteristic of
poor startability at low ambient temperatures is shared by all
diesel engines. The problem of startability is addressed in
car and truck diesel engines through the use of starting aides
such as glow plugs in the combustion chambers or intake air
preheaters. These technologies have not been used on diesel
locomotive engines. Because of combustion chamber
configuration and because of severe cylinder head design
problems which would be associated with the application of glow
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plugs to locomotive engines (see Chapter 8), intake air
preheating appears to offer the greatest potential for
incorporation into new locomotive engines and appears to be the
only approach with potential as a retrofit cold-start aid for
in-use locomotives. Determination of the practicality of
applying glow plugs or intake air preheating to new locomotives
and retrofitting of intake air preheaters to older locomotives
can only be made in cooperation with the manufacturers and
users of the locomotives.
Current locomotive designs preclude any considerations of
shut-down at ambient temperatures of 32°F and below because
there is no provision for preventing freezing of the coolant.
While the use of antifreeze in the cooling systems would appear
to offer a solution for the control of coolant freezing, three
problems are readily identifiable which will require resolution
prior to the successful use of antifreeze and consequently
prior to low temperature shutdown becoming practical. Two of
these problems have already been identified, i.e., engine
startability at temperatures below 50°F and coolant leakage.
Leakage of even a small volume of coolant containing antifreeze
into the oil can result in component failures. The need to
prevent contamination of the oil with coolant is, therefore,
substantially greater when antifreeze is employed. The third
problem associated with the use of antifreeze in locomotives
stems from the effects on engine cooling. Briefly, the
addition of antifreeze to the engine cooling water decreases
the rate of heat removal in the engine and the rate of heat
rejection at the radiator. If space is available on the
locomotive for a larger radiator, this segment of the problem
can be resolved, but at some cost. It is not presently clear,
however, what methods would be most suitable to increase the
heat rejection rate in the engine.
If the problems of engine startability at relatively low
ambient temperatures and coolant leakage can be overcome,
engine shutdown at temperatures approaching 32°F may become
practical.* If solutions to the problems associated with the
use of antifreeze can be found, locomotive shutdown at
temperatures lower than 32°F may become practical.
Cyclic starting, warming-up and shutting-down of
locomotives is probably not practical as a method of
reducing idle times and resolving cold starting problems
because: 1) repeated thermal cycling tends to worsen the
water leakage problem, 2) smoke and probably hydrocarbon
emissions are high during engine warm-up, and 3)
additional personnel would be required to perform this
function thereby increasing costs.
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Table 22, which was developed previously, shows the
percentage contribution of locomotive idling emissions to the
total railroad emissions for each type of locomotive based on
historical operational practices. Estimates of reductions in
emissions from locomotives through reductions in the time spent
at idle can be developed by deriving modified duty cycles and
the corresponding emissions. The factors which determine the
amounts to which duty cycles can be modified are engine
startability versus ambient temperature, operational
considerations of the trains which limit the amount of
shut-down which can be practiced and the effects of cold-start
emissions following a shut-down. Three scenarios are readily
identifiable for the relationship between engine shut-down and
restart versus ambient temperature. These scenarios are: 1)
that the engine can be started under essentially all ambient
temperatures, 2) that antifreeze continues not to be used and,
therefore, that the inclusion of starting aids is limited to
those which are effective at 32°F and above, and 3) that engine
startability is limited to 50°F and above.
Under the first scenario (startability is possible at all
temperatures), practical considerations of train operation are
assumed to limit shut-down to 60 percent of present idle time
and that emissions during the cold-starts are equal to
approximately 10 percent of daily idle emissions. Under this
scenario, idle emissions would be reduced by approximately 50
percent. The resulting reductions in overall railroad
emissions in AQCRs would be on the order of 17 percent for HC,
15 percent for CO and 7 percent for NOx.
Under the second scenario (engines can be shut-down at
temperatures above 32°F) the theoretical maximum amount of
engine shut-down can be estimated on a national annual basis
from the number of days when the ambient temperature does not
fall below 32°F. The theoretical maximum reduction in idle
time with this constraint is approximately 40 percent.[18] If
it is assumed that practical train operating constraints and
cold start emissions reduce this value by 20 to 25 percent, the
resulting projections for reductions in railroad emissions are
on the order of 10 to 11 percent for HC, between 8 and 9
percent for CO and between 4 and 4 1/2 percent for NOx.
Under the third scenario (shut-down at 50°F and above) the
reductions in emissions are estimated to about one-half of
those estimated for the second scenario, i.e., reductions in
HC, CO, and NOx emissions would be on the order of 5 percent, 4
percent, and 2 percent, respectively.
Not only do idling locomotives contribute to the pollutant
burden in a region but they consume fuel while performing no
useful work. While locomotive manufacturers and operators are
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already pursuing engine shut down to conserve fuel, the
increasing cost of fuel should favorably dispose both the
manufacturers and the operators to address the concept of
maximizing locomotive shutdown when not in active service. It
is presently not clear, however, what level of effort may be
employed by manufacturers to address problems associated with
engine shutdown and restart. It is equally not clear whether
railroads would utilize locomotive shutdown capabilities if
provided by manufacturers.
Table 23 summarizes the fuel consumption rates for an
average switch and transfer locomotive and for an average line-
haul locomotive as functions of throttle notch position and by
duty cycle (these in-use locomotive weighted values were
calculated using the same methodology as was used previously
for emissions). In the case of switch and transfer
locomotives, approximately 38 percent of the total daily fuel
usage by these units is consumed in the idle mode. The
comparable value for line-haul locomotives is approximately 12
percent when operating in an AQCR (i.e., on a 12 hour per day
basis) . Estimates of the monetary value of the fuel which
could be saved through locomotive shut-down are presented in
Chapter 8.
7.1.2 Limiting Use of Highest Power Settings When in Urban
Areas
Eliminating the use of throttle notch positions 6, 7 and 8
in metropolitan areas may be a method of providing a measure of
emissions reductions from this source (locomotives). The
practicality of this approach has, however, not been
established and it must be viewed as having a low potential for
success. As a minimum, the following conditions would have to
be met for this approach to be practical: 1) that the
locomotives assigned to each train under present operating
practices could perform the work required at reduced power
settings when in urban areas, and 2) that train schedules would
not be significantly affected. If these conditions can not be
met, disruptions in train schedules could result and a net
increase in emissions could result either from the addition of
locomotives to each train so as to maintain schedules or from
an increase in time for each trip. If the conditions could be
met, the estimates of the effects on locomotive emissions are
as follows. In the case of switch and transfer locomotives,
the reductions would be very small because of the existing
limited use of high throttle notch positions. For line-haul
locomotives, the projected per locomotive effects of
substituting throttle notch position 5 for the higher power
settings are reductions of 11 percent, 30 percent and 22
percent for HC, CO and NOx, respectively.
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Table 23
Locomotive Fuel Consumption - Average Values in AQCRs
Switch and Transfer
Locomotive Line-Haul Locomotive
Throttle
Notch tt/hr tt/dayl/ tt/hr
Idle 24 444 38 269
1 48 81 68 57
2 85 143 148 107
3 117 112 263 189
4 216 104 369 266
5 285 68 570 205
6 364 44 662 238
7 453 54 865 311
8 545 131 1,040 624
Dynamic Brake - - 124 30
Total 1,181 ' 2,296
I/ 24-hour/day duty cycle.
2/ 12-hour/day duty cycle in AQCRs.
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Ignoring any small benefit attributable to switch and
transfer locomotives, this change in the duty cycle, relative
to the historical cycle, offers the potential for about an 8 to
9 percent reduction in HC emissions, between a 26 and 27
percent reduction in CO emissions and about an 18 percent
reduction in NOx emissions from railroads in metropolitan areas.
7.1.3 Composite Effect of Duty Cycle Modifications
Adoption of both of the changes to the historical duty
cycles (i.e., reductions in idle time and substitution of notch
5 for notch 6, 7, and 8 operations) would be projected to offer
the potential for reducing railroad HC emissions by between 13
and 26 percent (the smaller reduction corresponds to 50°F
shutdown capability and the larger reduction corresponds to a
shutdown capability at all temperatures). Corresponding
potential reductions in CO emissions range from 30 percent to
42 percent while reductions in NOx emissions may range from 20
to 25 percent.
7.2 Application of Emission Control Technology
In the area of exhaust emissions characteristics, large
diesel engines used in locomotives tend to be similar to
smaller diesel engines used in trucks and passenger cars.
Generally, the control of exhaust emissions from diesel engines
pose significant problems with respect to smoke (particulate
material) and oxides of nitrogen, while posing lesser problems
with respect to hydrocarbons. Because carbon monoxide
emissions are inherently quite low, control of CO is not
considered to be a problem.
The literature did not contain data on the effects of
control techniques when applied to full-size locomotive
engines. Work which had been performed to assess the
effectiveness of control technologies on locomotive engines
employed relatively smaller engines and the results necessitate
an extrapolation to the full-size locomotive engine (Assessment
of Control Technologies for Reducing Emissions from Locomotive
Engines, 1973). It is also important to note that the engines
tested were all 2-stroke units and that the data would
therefore be most applicable to locomotives produced by EMD.
Directionally, the data should be useful with 4-stroke engines
(GE products) but quantification would be greatly in doubt.
Emission control techniques of general interest to diesel
engines which were considered in the study were: 1)
modification of fuel injection timing, 2) modification of
injector design, 3) exhaust gas recirculation, 4) internal
exhaust gas recirculation (reduced scavenging), and 5) water
injection. Each of these techniques is discussed below.
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Throughout these discussions, the effects will be expressed in
terms .of locomotive duty cycles as used in this study with the
exception of smoke which could not be quantified in these terms
because the lack of an appropriate data base. It must be
remembered that the duty cycles do not include any changes
which may recently have occurred to reduce engine idle time.
7.2.1 Modification of Injector Design
Results from testing with three types of injectors were
reported. The types of injectors tested were: spherical
valve, needle valve and low-sac. The older (at the time that
testing was performed), spherical valve design was being
replaced on in-use locomotives by the needle valve and low-sac
designs. Low-sac injectors are presently standard equipment on
EMD locomotives and are provided as replacement parts for older
EMD locomotives. The reported relative effects of the three
types of injectors were:
1. The low-sac injectors reduced hydrocarbon emissions
relative to the needle valve type on the order of 50 percent
for the switch and transfer duty cycle and about 15 percent for
the line-haul duty cycle (low-sac injector technology was
introduced by locomotive manufacturers as a method of reducing
HC emissions).
2. Low-sac type injectors resulted in NOx emissions
which were about 15 percent higher than those from the needle
valve type injector on the switch and transfer duty cycle and
about 30 percent higher on the line-haul duty cycle. Relative
to the spherical injectors, the needle valve type was
essentially equal on the switch and transfer duty cycle and
about 20 percent better on the line-haul duty cycle.
3. Smoke opacity measurements were essentially equal
for all injector types.
4. The low-sac injectors gave benefits of 20 to 25
percent in carbon monoxide emissions relative to the needle
valve type of injector on both duty cycles.
5. It was not possible to identify any effects on the
efficiency of fuel utilization associated with the different
types of injectors.
7.2.2 Modification of Injection Timing (Timing Retard)
Directionally, the results of retarding injection timing
(within reasonable limits) are to reduce oxides of nitrogen
emissions, to increase smoke, to have little effect on
hydrocarbon emissions and to tend to increase carbon monoxide.
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The effect on the efficiency of fuel utilization (fuel consumed
per unit of useful work performed) was not reported in the
data. Some penalty can, however, be anticipated and can
reasonably be expected to be on the order of 1-2 percent.
The effects of injection timing retard, based on the
locomotive duty cycles, are summarized below:
1. NOx emissions could be reduced by 25 to 30 percent
on both the line-haul locomotive duty cycle and switch and
transfer locomotive duty cycle.
2. Smoke opacity would be increased by 50 to 100
percent throughout the speed/power range of the locomotive when
needle type injectors were employed (old injector design).
With recent design (at the time that the data were collected)
low-sac injectors,* the increase in smoke emissions resulting
from injection timing retard was under 50 percent. Derating
the maximum power of the engines by 10 to 15 percent tended to
alleviate the increased smoke levels. It is important to note
that these data were expressed in terms of opacity and not in
terms of the mass of particulate emitted (mass emission
measurements were not performed).
3. Hydrocarbon emissions were generally unchanged as a
result of injection timing retard. A reduction of between 1
and 4 percent may, however, be indicated.
4. On the switch and transfer locomotive duty cycle,
carbon monoxide was almost unaffected (needle valve injectors
were associated with a reduction of a few percent and low-sac
injectors (newer design) were associated with an increase of a
few percent). On the line-haul locomotive duty cycle, carbon
monoxide would be projected to increase by approximately 20
percent as a result of retarded injection timing.
7.2.3 Exhaust Gas Recirculation
The referenced study investigated both cooled and uncooled
exhaust gas recirculation (EGR). Because the data for cooled
EGR were collected under laboratory conditions, the degree of
cooling provided was not constrained as it would be on a
locomotive. Those results were not judged, therefore, to be
representative of the effects of cooled EGR in locomotive
operation and are not included in this report. Application of
uncooled EGR resulted in the following effects:
Low-sac injectors have been standardized for use on new
EMD locomotives and are provided as replacement parts for
older EMD locomotives.
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1. Engine operation was unstable with exhaust gas
recirculation, especially at the maximum EGR rate which was
employed, i.e., 30 percent EGR level. Engine power was
generally reduced as a result of the use of EGR. The amount of
power loss was, however, not clearly quantified. The effects
on emissions given below are based on a maximum EGR rate of 20
percent where engine operation was still relatively stable.
2. NOx emissions were decreased by approximately 30
percent on the switch and transfer duty cycle and by
approximately 50 percent on the line-haul duty cycle.
3. Smoke opacity was increased by a factor of
approximately two at low-power conditions and increased by a
factor of six to seven at high-power conditions.
4. Twenty percent EGR rates had little effect on CO
under the switch and transfer duty cycle conditions but
increased CO by a factor of between two and one-half and five
on the line-haul duty cycle, dependent upon the type of
injector being used. The low-sac injectors which were
introduced to reduce HC emissions, were associated with the
greatest increase in CO.
5. Reductions in hydrocarbon emissions associated with
the use of EGR were on the order of 25 to 50 percent on the
switch and transfer duty cycle and on the order of 10 to 20
percent on the line-haul duty cycle.
6. Determination of the effects of EGR on the
efficiency of fuel utilization could not be made because of
insufficient data. The increases in CO and smoke emissions,
are however, indicative of decreased efficiency in fuel
utilization (a one percent penalty will be assumed).
7.2.4 Reduced Scavenging (Increased Internal Exhaust Gas
Recirculation)
On the 2-stroke engine tested, this approach was
accomplished by bleeding a portion of the intake air charge at
the air box, i.e., reducing the amount of cylinder scavenging.
A similar effect would be achieved on a 4-stroke engine by
increasing valve overlap if very little overlap were presently
used or by air bleed as was used on the 2-stroke engine. The
reported results were as follows:
1. With an air bleed rate of approximately 35 percent,
a reduction in power output, on the order of 10 to 20 percent
was observed at the high power settings. Engine roughness was
experienced at the higher air bleed rates investigative, i.e.,
at air bleed rates greater than 20 percent. The effects on
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emissions as summarized below are, therefore, limited to air
bleed rates of 20 percent.
2. NOx emissions on the switch and transfer duty cycle
were reduced approximately 15 percent and on the line-haul duty
cycle by between 10 and 15 percent.
3. Smoke opacity increased on the order of 50 percent
at low power and up to 300 percent at maximum power.
4. Hydrocarbon emissions were little changed on both
duty cycles when the low-sac injectors were utilized. Needle
valve injectors in conjunction with the air bleed resulted in
approximately a 40 percent reduction in HC emissions on the
switch and transfer duty cycle, and approximately a 20 percent
reduction on the line-haul duty cycle.
5. Carbon monoxide emissions were reported to decrease
by 30 percent on the switch and transfer duty cycle and to
increase by 30 percent on the line-haul duty cycle when needle
valve injectors were in-use. The results with the low-sac
injectors were a 15 percent increase in CO on the switch and
transfer duty cycle and a factor of three increase on the
line-haul duty cycle.
6. The effects on the efficiency of fuel utilization
could not be determined from the data. The increases in CO and
smoke emissions which were observed are, however, indicative of
reduced combustion efficiency and probably reduced fuel economy
(a one percent penalty will be assumed).
7.2.5 Water Injection
Application of water injection to locomotives will pose
such practical in-use problems as: 1) freezing in cold
weather, 2) corrosion in the water injection system and
possibly in the engine, 3) storage capacity on the locomotive
for the large volume of water required (75 to 100 percent of
fuel tank volume), and 4) the availability of water of suitable
purity (contaminants in the water will result in build-up of
deposits in the water delivery system and in the engine). The
reported effects on emissions of water injection rates equal to
75 percent of fuel flow rates were as follows:
1. NOx emissions were reduced between 15 and 20 percent
on both duty cycles with both the low-sac injectors and the
needle valve injectors.
2. There was little overall effect on smoke opacity.
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3. Hydrocarbon emissions were decreased (needle valve
injectors) by about 50 percent on the switch and transfer duty
cycle and by 20 percent on the line-haul duty cycle. With the
low-sac injectors, hydrocarbon emissions increased between five
and 15 percent.
4. Carbon monoxide decreased by approximately 5 percent
on both duty cycles with the low-sac injectors and by an equal
amount on the line-haul duty cycle when the needle valve
injectors were used. Carbon monoxide increased by 25 percent
on the switch and transfer duty cycle when the needle valve
injectors were used.
5. The report indicated a slight improvement in power
and, as with the other emission control techniques, the effect
on the efficiency of fuel utilization could not be determined
(no fuel economy penalty is assumed).
In summary, the results of the study show similar trends
for locomotive diesel engines as are observed with other diesel
engines, i.e., control techniques which benefit one pollutant,
for example, NOx, often result in an increase in another
pollutant, for example, smoke (particulate). It is worth
noting, however, that progress is being made by other diesel
engine manufacturers, e.g., those making heavy-duty diesel
truck engines, in controlling the trade-off between these
pollutants. It is not unreasonable to expect that similar
benefits could be realized in the case of locomotive engines.
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8.0 COST AND COST-EFFECTIVENESS ESTIMATES
Following the approach used in the previous chapter,
estimates of costs (1984 dollars) are divided into two general
types of control procedure. The costs are those associated
with changes in operating practice (duty-cycle modifications)
and costs associated with the application of emission control
technology. The cost-effectiveness estimates are presented in
the section which follows the cost estimates.
Estimates of costs shown in this chapter were developed
from meetings between EPA and locomotive manufacturers and from
costs associated with emission controls used on automobiles and
trucks. While both manufacturers of locomotives cooperated
with EPA in developing a general understanding of the effects
of adding emission control systems to locomotives, neither felt
that reliable estimates of costs could be developed at this
time. One basis for their uncertainty was the lack of detailed
design information associated with the application of emission
controls to locomotives and consequently the unavailability of
a basis for the development of accurate costs. The second
basis for the uncertainty is the significant difference which
exists between the high volume manufacturing processes used on
automobiles and trucks and the very low volume manufacturing
processes used on locomotives. Extrapolations of the costs of
locomotive components from costs associated with automobiles
and trucks are, therefore, subject to substantial uncertainty.
For the reasons given above, it is very important to
stress that the costs shown in this chapter should be viewed as
first order approximations which are subject to change.
8.1 Duty Cycle Modifications
8.1.1 Engine Shutdown When Not in Active Service
Estimates of the costs of changes to locomotives which may
be required to achieve engine shutdown can be grouped into
three categories. In decreasing order of magnitude the costs
would be associated with: 1) engine shutdown capability at
temperatures below freezing, 2) engine shutdown capabilities at
temperatures just above freezing and 3) engine shutdown
capabilities at 50°F and higher.
Problems requiring resolution for engine shutdown at
temperatures below freezing are: engine startability, the need
to improve heat dissipation in the engine and the radiator as a
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result of the use of antifreeze, prevention of fuel "waxing,"*
limiting cold - start emissions, provision for adequate
lubrication at startup, provision of lubricants which perform
adequately when both hot and cold, elimination of coolant
leakage into the crankcase and cylinders if antifreeze is used
and provision for removal of any coolant which may leak into
the cylinders where antifreeze is used. With engine shutdown
at temperatures just above freezing, the problems associated
with the use of antifreeze are avoided and the severity of the
fuel waxing and lubrication problems are reduced. With
shutdown limited to 50°F or higher, the problems are reduced to
the control of cold start emissions and coolant leakage and to
a lesser extent provision for adequate lubrication immediately
following start up.
Potential methods of resolving the problems and the
associated costs are addressed in the following paragraphs.
The total cost for each of the categories are developed by
summing the costs of appropriate remedial actions. Credits for
anticipated fuel savings are incorporated for each category.
8.1.1.1 Engine Startability
Ignition of the fuel in a diesel engine is achieved by
compressive heating of the air in the cylinders to a
temperature which is sufficiently high to cause the fuel to
ignite. Two factors are primary contributors to the problem of
starting a cold diesel engine. The first factor is the
relatively low temperature of the air after compression because
of the low initial temperature of the air. The second factor
is the cooling of the air during compression by the cold
surfaces of the cylinder wall and combustion chamber. In
combination, these two factors play the critical role in
establishing the ambient temperature below which a given diesel
engine will not start without the use of some form of starting
aid.
Fuel "waxing" - diesel fuel contains some wax which
solidifies at low temperatures and prevents the fuel from
flowing. When the engine is in operation, the quantity of
fuel delivered to the engine is greater than that required
to operate the engine. The excess fuel is returned to the
fuel tank. As the fuel flows through the fuel
distribution lines on the engine, it is warmed and the
warm excess fuel prevents fuel waxing in the tank and
supply lines.
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The most readily identifiable methods of improving the
startability of diesel engines are; the introduction of
electrical heating elements into the combustion chamber(s)
(glow plugs), heating of the air before it enters the engine,
use of a readily startable auxiliary engine to rapidly crank
the main engine for a prolonged period of time coupled with
heating of the intake air by the exhaust gases of the auxiliary
engine, the use of an auxiliary starting fuel and the use of a
starting fluid which is introduced into the intake air.
Functionally, glow plugs provide a hot-spot in the
combustion chamber as well as some heating of the metal which
forms the surface of the combustion chamber and some of the air
in the chamber. Glow plugs are the standardized method whereby
starting is achieved in the relatively small, indirect
injection (IDI) diesel engines used in passenger cars. Glow
plugs are seldom if ever used in the relatively larger, direct
injection (DI) diesel engines used in heavy-duty trucks. The
reason for this difference in the application of glow plugs is
attributable primarily to the differences in the combustion
chambers and to a lesser extent to the differences in engine
size. In an IDI engine, the combustion chamber consists of two
interconnected chambers with the fuel being injected into only
one of the chambers. As a result, heating by a glow plug can
be concentrated in the section of the chamber where fuel
injection and consequently ignition occurs. In a DI engine, a
single chamber is employed and as a result, the problem of
providing sufficient and appropriately located heating is
substantially greater than is the case for an IDI engine.
Because of the differences in combustion chamber configuration,
significantly less electrical energy is required for the
successful heating and consequently starting of an IDI than
would be required in a DI engine of comparable size. In
addition, air which is warmed by the glow plug tends to be
retained in the pre-chamber of the IDI engine during cranking
while the air in the cylinders of the DI engine tends to be
expelled during cranking. Locomotive engines are of the DI
type with individual cylinder volumes which are between four
and six times larger than those in heavy-duty truck engines.
As a result of these factors, it is reasonable to expect that
multiple glow plugs would be required in each cylinder of a
locomotive engine so as to achieve the necessary heating. It
is also reasonable to expect that each glow plug would be
significantly larger than those used in passenger car diesel
engines. A very substantial increase in the size of locomotive
batteries would result from the use of glow plugs.
The tasks required for the application of glow plugs (the
first option) to locomotive engines are the development of a
new cylinder head design that would accommodate the glow plugs
while retaining other necessary characteristics, provision for
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an adequate electrical energy storage system and an electrical
wiring and. control system interconnecting the glow plugs and
the batteries.
Redesign of the cylinder heads to accommodate the use of
glow plugs is expected to be very difficult. The reasons are
that space allocated for the application of glow plugs must
come from that presently allocated to cylinder head cooling and
that the use of four valves per cylinder (existing design
practice necessary to facilitate the high power output
required) dictates glow plug placement in relatively
unfavorable operational positions. Any reduction in either
cooling capability or the size or number of valves will
translate into an unacceptable reduction in the power of the
engine. Because of the severity of the anticipated problems,
the cost to each of the two locomotive builders for developing
new cylinder heads is projected to be between $1,000,000 and
$1,500,000. Recovery of these costs over five years with total
yearly locomotive production of 1,200 units results in a per
locomotive cost of between $340 and $500. Increased
manufacturing costs per cylinder head would be in the range of
$30 to $40. Locomotive engines employ a separate cylinder head
for each cylinder and the majority of engines sold are 16
cylinder units (8, 12, 16 and 20 cylinder engines are
available). On a per locomotive basis the manufacturing costs
for the redesigned cylinder heads are, therefore, expected to
be between $480 and $640. On a per cylinder head basis, the
redesign and manufacturing costs equal between $50 and $70.
These costs are between six percent and ten percent of the
present price ($700-$800) of a replacement cylinder head.
The next cost component of the glow plug assisted starting
approach to resolving low temperature startability is the cost
of the glow plugs. Using the price of a replacement glow plug
for a passenger car diesel ($20) as a guide, the cost of a glow
plug for a locomotive engine is projected to be between $30 and
$40. The higher cost relative to the passenger car unit
results from the size increase (heating capacity) and low
production volume of the locomotive units. If two glow plugs
per cylinder can perform the necessary function, the per
locomotive cost would be between $960 and $1,280. The per
locomotive cost could increase to between $1,920 and $2,560 if
four glow plugs were required per cylinder.
The remaining cost components of the glow plug assisted
starting system would come from the increase in the size of the
battery and the starter and from the electrical wiring and
controls which would interconnect the battery and the glow
plugs. A two fold increase in battery size is projected so as
to provide an adequate energy supply for the glow plugs as well
as the increase in engine cranking load which occurs at low
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temperatures. The price of the batteries which are presently
used on locomotives is between $3,500 and $5,500. This price,
plus an additional $100 for enlargement of the battery box is
used to represent the cost for the increase in battery size.
The price of a starter for a locomotive engine is approximately
$1,000 (two are used). This price can be expected to increase
by about 15 percent because of the increase in power necessary
to crank the engine at low ambient temperatures. The
incremental cost increase for the starter is, therefore,
estimated to be about $300. The wiring harness for
transmitting the energy from the batteries to the glow plugs,
its locating parts and the system for automatically controlling
the supply of energy to the glow plugs could cost between $300
and $500. The first cost of the glow plug assisted starting
approach is the sum of the costs of the component parts and is
projected to be in the range of $5,980 to $10,100.
Over the lifetime of the locomotive (assumed to be 15
years) it is reasonable to expect that replacement batteries
will be purchased twice and that 25 percent of the glow plugs
will require replacement. The discounted cost of these
components would be between $4,200 and $6,900 including a labor
cost for replacement of the defective components.
The second procedure which has been identified as a
potential starting aid is preheating of the intake air. Design
and development costs for this approach should be less than
those for a new cylinder head. A per locomotive cost of
between $100 and $200 is used assuming a level of effort which
is about one-third that required for a cylinder head redesign.
The first set of components of this system would be the
heating components which would consist of a fuel atomizer, fuel
pump, combustion air blower, ignition system, combustion
chamber and electrical supply, assuming that diesel is the fuel
used in the heater. The second set of components of the system
would consist of the heat delivery unit which could take more
than one form. If the intake air preheater was mounted between
the engine air filter and the turbocharger with its hot
combustion gases being mixed with the air entering the engine,
a relatively simple piping connection would form the heat
delivery unit. A second method of heat delivery would be to
mount the heating unit on the intake manifold downstream of the
turbocharger and the intercooler with direct mixing of the hot
combustion products and the intake air. This method of
installation would require a relatively minor modification of
the intake manifold and a one-way valve to prevent the loss of
pressurized intake air during engine operation. The third
method of supplying heat to the intake air would be by the use
of a heat exchanger located either before the turbocharger or
after the intercooler. While the use of a heat exchanger would
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be the most complex and costly approach of the three, it would
remove, problems caused by water condensation, intake air
dilution and the build up of deposits in the engine intake
system associated with the other approaches. The heat
exchanger would have to be relatively large so as to minimize
flow restrictions in the engine intake air system.
The cost of the heating components of the intake air
heating system can reasonably be expected to be between $1,000
and $1,500 per locomotive. The cost of the heat delivery
components using a heat exchanger is projected to be between
$2,000 and $3,000 per locomotive and include the heat exchanger
cost, the incremental cost for the redesigned intake manifold
and an exhaust pipe for the heater. In addition to the cost of
the intake air heating system, provision would have to be made
for additional battery capacity so as to effectively crank the
engine at low ambient temperatures. This additional battery
capacity is expected to necessitate about a 50 percent increase
in the size of the present batteries. This incremental cost is
projected to be between $1,800 and $2,800 including $50 for a
larger battery box and retaining hardware. The incremental
cost for the starter would be the same as that associated with
the use of glow plugs and is approximately $300. The cost of
the intake air heating system is, therefore, projected to be
between $5,200 and $7,800.
Lifetime discounted costs for battery replacement and
maintenance of the heater system are estimated to be between
$3,000 and $4,000.
The third method which was identified as a potential
method for achieving starting of a cold locomotive diesel
engine was the use of a readily startable auxiliary engine.*
With this approach, achieving the required temperature of the
air in the cylinders at the end of compression would be
obtained by two paths. One path would be the heating of the
air entering the main locomotive engine by the hot exhaust
gases of the auxiliary engine. The other path would be the
heating of the walls of the combustion chamber by the heat of
compression through prolonged cranking of the main engine prior
* It is questionable whether space is available in a
locomotive for the auxiliary engine and associated
hardware. The cost estimate for this approach to
achieving low temperature startability is, however, based
on the assumption that space can be made available. If
space cannot be made available for the auxiliary engine
within existing locomotive overall dimensions, use of an
auxiliary starting engine will be precluded because of
size constraints which are detailed in Section 8.2.5.
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to the introduction of fuel. The components required for this
approach are the auxiliary engine, speed reduction gearing
between the auxiliary engine and the main locomotive engine, a
means for coupling and decoupling between the two engines and a
heat exchanger in the intake system of the main engine. The
cost of the auxiliary engine, reduction gearing and
engine-to-engine coupling is projected to be in the $5,000 to
$7,000 range. The cost of the heat exchanger and the changes
to the intake manifold would be similar to those for the
preheater approach and would be between $2,000 and $3,000 per
locomotive. On a per locomotive basis, the development costs
would be similar to those associated with intake air
preheating, i.e., between $100 and $200. If the use of an
auxiliary engine for starting was viewed as a complete
changeover from the use of an electric starter, these costs
could be reduced by the cost of the electric starter ($2,000)
plus a reduction in battery size by a factor of two to three.
The cost savings in batteries could, therefore, be between
$1,500 and $3,500. The incremental cost increase for an
auxiliary engine for starting of the main engine is developed
by combining the sum of the component costs and savings and is
projected to be between $1,600 and $6,700. Lifetime discounted
cost for maintenance of the auxiliary engine and drive systems
should be between $500 to $1,000.
The fourth method which was identified for enhancing
startability at low temperatures is the use of an auxiliary
starting fuel which will ignite more readily than the primary
fuel. The changes to the locomotive which would be required
with this approach are the addition of a fuel tank for the
auxiliary fuel, a system for purging the primary fuel from the
injection system prior to engine shutdown and an increase in
battery and starter size. The cost of an auxiliary fuel tank
and the addition of a fuel selector valve to the fuel delivery
line would not be large if space were available on the
locomotive for the fuel tank. Assuming that space is available
for a relatively small auxiliary fuel tank, the cost should not
exceed $500. If space is not available for the auxiliary fuel
tank, this approach for achieving enhanced engine startability
may not be a viable option because locomotives are already at
the weight and length limits imposed by track constraints i.e.,
locomotives cannot be enlarged to provide space for the
auxiliary fuel tank. The incremental cost for the larger
batteries and starter would be equal to that of the intake air
preheat system; i.e., about $2,100 to $3,100. The total cost
of the auxiliary fuel approach is projected to be about $2,600
to $3,600. Maintenance and battery replacement costs should be
equal to those for an intake air preheating system, i.e., $3000
to $4000. While the cost of this approach is relatively low,
its effectiveness as a starting aid is also low relative to the
three procedures for which cost estimates have previously been
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developed. It is unlikely, therefore, that this approach would
be employed where reliable starting was required at
temperatures much below freezing.
The final approach for improving startability is that
which is presently employed on some engines at approximately
50°F and for all engines at temperatures just below 50°F. This
approach is the manual introduction of a small amount of ether
into the intake system just prior to cranking of the engine.
While the cost of this approach is minimal, it cannot be
considered as a viable starting aid at temperatures below 40°F
to 45°F.
Of the five methods for achieving low temperature starting
of locomotive engines, two (glow plugs and intake air heating)
presently appear to offer the greatest potential for use.
Because of the anticipated problems associated with the
application of glow plugs and because of the potential cold
start emission control benefits of intake air preheating, this
is the procedure which would probably be employed.
The estimates of the costs for the types of starting aides
which have been considered are summarized in Table 24 for ease
of reference.
8.1.1.2 Use of Antifreeze and Control of Fuel Waxing
Once an ability to start locomotives at low ambient
temperatures is in place the need arises for the prevention of
freezing of the coolant and fuel waxing during engine
shutdown. Freezing of the coolant can be prevented by the use
of the appropriate quantity of antifreeze. Use of antifreeze
leads, however, to a reduction in the rate of heat dissipation
at the radiators and from the walls of the combustion chambers
and cylinders to the coolant.
Increasing the heat dissipation at the radiator can be
achieved by the use of a larger radiator. The required
increase in radiator size is expected to be on the order of 15
to 20 percent. The incremental cost increase for the radiator
enlargement is projected to be between $1,000 and $1,500 based
on existing radiator prices of between $10,000 and $12,000.
This cost increase is based on the assumption that there will
be no change in the existing fans and fan drives for moving air
over the radiator. Obtaining the necessary space in the
locomotive for the larger radiator is expected, however, to
pose a problem. The cost of modifications to locomotives to
secure the necessary space could range from $1,000 to $5,000
per locomotive and would depend upon the extent of the changes
required.
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Table 24
Summary of Costs: Engine Starting Aides
Starting Aide
Glow plugs
Cylinder head and glow plugs
Battery, Starter, Wiring
Replacement batteries
and glow plugs
Total
Cost per Locomotive ($)
First
1,780-3,700
4,200-6,400
Maintenance
4,200-6,900
5,980-10,100 4,200-6,900
Applicability
All temperatures
Intake Air Preheat
Heater
Battery, Starter
Replacement batteries
and heater maintenance
Total
3,100-4,700
2,100-3,100
3,000-4,000
5,200-7,800 3,000-4,000
All temperatures
Auxiliary Engine
Engine, Drive, Heat exchanger
Starter, Battery
Maintenance
7,100-10,200
(5,500-3,500)
500-1,000
All temperatures
Total
1,600-6,700 500-1,000
Auxiliary Fuel
Tank, Plumbing
Battery, Starter
Total
500
2,100-3,100 3,000-4,000
2,600-3,600 3,000-4,000
Above freezing
Ether
Above 40°to 45°F
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It is not fully apparent how heat dissipation to the
coolant could be adequately increased in the combustion chamber
and cylinder liner regions of the engine without a major and
very costly engine redesign. The most direct method for
increasing heat dissipation to the coolant would be by an
increase in the surface area of the engine components which are
in contact with the coolant through the addition of fins or
spines. There is little if any potential for increasing heat
dissipation to the coolant in the cylinder head by this method
because spines are already employed in the design. Increasing
the surface area of the cylinder liner which is in contact with
the coolant through the addition of fins or spines does not
appear to be possible without a major engine redesign because
of the present inability to insert the liners into the engine
if fins or spines are employed. Increasing the rate of flow of
the coolant through the engine may be a method for resolving
the cooling problem. There is, however, no data to support the
validity of this approach.
A second area where significant uncertainty exists with
respect to methods of resolving identifiable problems is that
of achieving control over coolant leakage. Locomotive
manufacturers indicate that changes have recently been made to
the engines which reduce the potential for coolant leakage into
the crankcase and into the cylinders. These changes do not,
however, provide the degree of confidence for the control of
coolant leakage which would be required when antifreeze is used
in the coolant. Because of the high cost of repairing an
engine damaged by lubricant contamination as a result of
leakage of antifreeze into the crankcase (an estimate of
$50,000 to cover disassembly and cleaning followed by
rebuilding with new cylinders, pistons, crankshaft, and
bearings was provided by a manufacturer) and the time that the
locomotive would be out of service for repairs, every effort
can be expected to be made to prevent this type of leak.
If a major redesign were necessary, the cost can
reasonably be expected to be between five and ten times that
which was estimated for the redesign of a cylinder head; i.e.,
from a low of $10,000,000 to a high of $30,000,000 for the two
manufacturers. Allowing for an increase in manufacturing cost
associated with the redesign, the cost increase per locomotive
can reasonably be expected to be in the range of $3,000 to
$6,000.
The first cost increase attributed to the use of
antifreeze in locomotive engines is the sum of the costs of the
engine redesign, radiator enlargement and the cost of the
antifreeze. These costs total to between $5,300 and $12,800
and include 200 gallons of antifreeze at $1.50 per gallon.
Over the life of the locomotive, the discounted cost for
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antifreeze for cooling system makeup and coolant changes would
be approximately $2,500.
Problems of fuel waxing may be controlled either by the
use of a fuel which will not exhibit a waxing problem at
prevailing ambient temperatures or by maintaining the fuel
during shut-down at a temperature sufficiently high to prevent
the formation of wax crystals. Changing from the grade of
diesel fuel which is presently used in locomotives to a grade
which would not exhibit the problem of waxing until a very low
ambient temperature was reached is not considered to be a
totally viable solution. At a minimum, the reasons for the
undesirability of this approach are twofold. First, fuel
producers would have to incorporate a portion of the fuel
presently produced for such uses as jet aircraft into the
diesel fuel for locomotives. This change in the locomotive
fuel blend could result in problems of adequate availability of
other fuel types. Second, the price of the fuel would be
higher than that of presently used locomotive fuel. Assuming
that the price penalty would be five percent (i.e., 5 cents per
gallon) applicable to the fuel consumed during the coldest
periods of the year, i.e., about one-third of the fuel used by
the railroads, the annual increase in fuel cost would be about
$67 million (present annual consumption of about four billion
gallons of fuel at $1 per gallon) or about $2,800 per
locomotive per year (discounted cost of approximately $22,200
over a 15 year life).
Maintaining either all or part of the fuel at a
temperature above that at which waxing would occur could be
achieved by: 1) the addition of a fuel heater, 2) insulating
the fuel tank to reduce the rate of cooling of the fuel and the
amount of energy supplied by the fuel heater, and 3) the
provision of a fuel drain back system which would remove all
fuel from unheated regions of the fuel delivery system (fuel
supply pump, filters, distribution and return lines). An
electric fuel heater powered by the locomotive battery may be
practical if the duration of each engine shut down was limited
to between 8 to 12 hours and if only a small fraction of the
total fuel volume of 3,000 gallons was warmed. With this
approach, rewarming of the majority of the fuel could be
achieved by piping engine coolant through the fuel tank once
the engine had started and warm-up was underway. Provision for
fuel heating under longer periods of engine shut down would
require the use of an external burner system to prevent
excessive discharge of the batteries. The cost of the
electrical fuel heater approach is projected to be in the range
of $500 to $1,000 to cover the heater, its controls,
partitioning of the fuel tank, fuel drain back system and
provision for heating the main fuel tank by engine coolant.
The cost of a burner system would be in the range of $1,000 to
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$2,000 for the burner, its fuel and air delivery systems, its
controls and the fuel drain back system.
The costs associated with the use of antifreeze and the
control of fuel waxing are summarized in Table 25.
8.1.1.3 Cold Start Emissions
Three emission species can pose problems with respect to
their emission rate during diesel engine warm up following a
start from low ambient temperatures. The emission species are
smoke (particulate material), carbon monoxide and
hydrocarbons. Primarily, poor combustion in a cold diesel
engine is caused by low air temperatures at the end of
compression which results in the failure of some of the fuel to
ignite and by flame quenching prior to the completion of
combustion for the remainder of the fuel. Because the problem
of elevated emission rates following a cold start is primarily
the result of low temperatures in the" combustion chamber,
pre-heating of the intake air, the fuel and reductions in the
time required for total engine warm-up would tend to reduce
these emissions. As was stated previously, the use of an
intake air preheater is probably the most viable approach for
enhancing cold engine startability. While this approach
appears to offer the most reliable method for achieving a cold
start, it also offers a method of reducing cold start
emissions. Operation of the intake air preheater both before
engine cranking is initiated and for some time after the engine
has started would tend to reduce cold start emissions. Heating
of the fuel by the intake air preheater before engine starting
and during engine warm up would also tend to reduce cold start
emissions. The cost of adding a fuel pre-heating element to
the intake air preheater should not exceed a couple of hundred
dollars for the heat exchanger and the necessary piping and
valves to divert the fuel to the preheater during start up.
Reducing the time for total engine warm-up is the third
temperature related method for reducing cold start
emissions. This could be achieved by the introduction of a
thermostat* or similar method of isolating the coolant in the
engine from the remainder of the coolant in the system. This
coolant isolation would limit the volume of coolant which has
to be warmed during engine warm up and would result in some
reduction in warmup time. The per locomotive cost for the
changes to the cooling system necessary to achieve a reduction
* One locomotive manufacturer expressed concern with respect
to the effects on railroad operations of a thermostat
failure. The concern expressed was for the blockage of
the tracks because the locomotive would become inoperable
when a thermostat failed in the closed position.
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Table 25
Summary of Costs:
Use of Antifreeze and Fuel Waxing Control
System
Use of antifreeze
Radiator
Space Modifications
Cylinder Redesign
Antifreeze
Total
Cost Per Locomotive ($)
First Maintenance
1,000-1,500
1,000-5,000
3,000-6,000
300
5,300-12,800
0
0
0
2,500
2500
Fuel
0
0
0
0
Use of different
fuel blend
22,200
Fuel Heating
Electrical
Auxiliary heater
500-1,000
1,000-2,000
0
0
0
0
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in engine warmup time is expected to be on the order of $500 to
$1,000. Assuming the use of intake air preheating for engine
startability, the incremental cost of these approaches to
reducing cold start emissions is projected to be between $700
and $1,200 per locomotive.
8.1.1.4 Lubrication Changes
Two changes in engine lubrication are expected to be
necessary as part of any effort to increase the amount of
engine shut down which can be practiced. These changes are
addressed below.
An accelerated rate of engine wear is a problem with all
engines during cranking and immediately after starting because
of poor lubrication during this period. On engines where the
desired period of useful operation is very long; e.g.,
locomotive engines, high wear rates associated with engine
starting can be a significant problem especially when the
number of cold starts is to be increased because of an increase
in the number of engine shutdowns. Cold start wear rates may
be reduced by the addition of an electrically driven auxiliary
oil pump which would deliver lubricant to all parts of the
engine prior to cranking. The cost of adding this system (oil
pickup, pump, drive motor, plunging and check valve) would be
on the order of $500 to $1,000 per locomotive.
The second change in engine lubrication which can
reasonably be expected to be required is the need to use an oil
which will flow when cold and which will also provide good
lubrication when hot. Oils of this type are used almost
exclusively in automobiles and are known as multi-viscosity
oils; i.e., the oil exhibits the characteristics of a low
viscosity oil when cold and of a high viscosity oil when hot.
Availability of multi-viscosity oils for diesel locomotive
engines is not expected to be an insurmountable problem. Some
increase in the cost of multi-viscosity oils relative to the
oils which are presently used is, however, anticipated. On the
basis of a cost differential of 20 percent between the two
types of oils,* a cost of $3 per gallon for oils which are
presently used and a lifetime oil usage of 65,000 gallons to
70,000 gallons for initial oilfill, oil changes and make up
oil, the projected cost increase is between $39,000 and $42,000
over the 15 year locomotive lifetime. As a discounted cost,
these values would represent a cost of between $21,000 and
$22,000.
Cost differential is based upon the difference of about 20
percent which currently exists in the automotive market
for these oils (at discount outlets).
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A summary of the costs of reducing cold-start emissions
and in lubrication changes is given in Table 26.
8.1.1.5 Fuel Savings from Engine Shutdown
Under the three temperature dependent engine shutdown
scenarios, the estimated reductions in idle time are 60
percent, 40 percent and 20 percent for shutdown capability
under all temperatures, just above 32°F and at 50°F and above,
respectively. Combining these values with the idle fuel
consumptions shown in Table 23, weighted by the ratio of
line-haul to switch locomotives* and allowing for fuel used
during cold starts (assumed to be 10 percent of fuel saved by
shutdown) results in annual fuel savings per locomotive of
approximately 8,000 gallons, 5,300 gallons and 2,700 gallons
for each scenario. With a fuel cost of $1 per gallon, a
locomotive life of 15 years and a discount rate of 10 percent,
the lifetime savings in fuel are approximately $63,500, $42,000
and $21,400, respectively.
8.1.1.6 Composite Costs for Engine Shutdown
As was previously indicated, three levels of temperature
related costs can be associated with engine shutdown when the
locomotive is not in service. These costs are dependent on the
severity of the problems associated with shutdown and restart
and are based on the ambient temperature at which shutdown is
desired. The three temperature scenarios are: 1) shutdown
capability at temperatures below freezing, 2) shutdown
capabilities at temperatures just above freezing, and 3)
shutdown capabilities at approximately 50°F and above.
To achieve shutdown capabilities at temperatures below
freezing, costs would accrue from the provisions for engine
startability at very low temperatures, use of antifreeze,
control of fuel waxing, reductions in cold start emissions and
changes in lubrication. The cumulative cost for this approach
is expected to be between $38,700 and $53,300 assuming that
intake air preheating would be employed. If other approaches
to achieving low temperature startability were to be employed,
the cumulative cost could range between $32,600 and $58,500.
The lifetime savings resulting from reduced fuel usage is
estimated to be about $63,500.
With engine shutdown constrained to temperatures just
above freezing, it is again probable that the intake air
* The ratio is approximately 3.93 line-haul locomotives per
switch locomotive as derived from the number of
locomotives shown in Table 14.
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Table 26
Summary of Costs:
Reducing Cold Start Emissions and Lubrication Changes
Cost Per Locomotive ($)
First Maintenance
Reducing cold start emissions
Fuel Preheater 200 0
Thermostatic Control 500-1,000 0
Total 700-1,200 0
Lubrication changes
Auxiliary Pump 500-1,000 0
Improved Oils 0 21,000-22,000
Total 500-1,000 21,000-22,000
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preheater would be preferred because of its ability to provide
engine .startability as well as reducing cold start emissions,
that changes in lubrication would be used and that the use of
antifreeze would be avoided. The cumulative cost for this
approach is projected to be between $30,900 and $38,000. The
lifetime savings in fuel is projected to be about $42,000.
Locomotive manufacturers consider 50°F as being the lower
limit of the temperature region in which new locomotives can be
reliably started. There are, therefore, no new costs
attributable to engine shutdown when temperatures are 50° and
above. The lifetime savings in fuel are projected to be about
$21,400.
8.1.2 Restricted Use of High Power Settings in Urban Areas
The assumption underlying this concept for the reduction
of emissions from line-haul locomotives is that the power
required to propel the train up grades and at scheduled speeds
when the train is outside of urban areas exceeds similar power
requirements when the train is in urban areas. It is also
assumed that a reduction in the speed of the train when in
urban areas would not be large enough to significantly impact
either the train schedules or the total time of locomotive
operation in urban areas.
If the underlying assumptions are correct, small cost
increases due to small schedule changes and increases in train
operator working hours can be expected to be either partially
or wholly recovered through savings in fuel usage.
If the underlying assumptions are in error, the costs
could be substantial and the net effect on railroad emissions
could be negative; i.e., emissions could actually be
increased. The potential for significant costs stems from the
reduction in the effectiveness of utilization of existing
railroad facilities (track, locomotives, and railcars) caused
by an overall slowing of the system and from the need to
purchase additional equipment to restore the speed of the
system where railroad customers could not accept a slowdown.
Development of even a rough estimate of the cost attributable
to a reduction in the effectiveness of utilization of existing
equipment would require information on existing capitalization
and amortization schedules. This information is not
available. If it is assumed, however, that a general slowing
of the system by five percent could result from this
operational change and that just the locomotive fleet size was
increased by five percent to compensate, the cost would be
approximately $1.5 billion for new locomotives. Changes in the
speed of the railroad system which were either less than or
greater than five percent would be expected to result in
proportionally either less or greater costs.
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The potential for the loss of all of the emission benefits
which were previously estimated for this approach stems from
the emission and power characteristics of the locomotives.
Locomotive emission rates for HC and NOx, when expressed in
terms of mass per unit of time, are approximately halved by
changing from throttle notch eight to notch five. The power of
the engine is also reduced by approximately one-half as a
result of a change between these two notch positions. If the
time that a line-haul locomotive spends in an urban region
(leaving, entering, or passing through) were to double* as a
result of the reduction in power due to operation in notch five
versus notch eight, all apparent emission benefits from the
change would be lost.
Estimates of the costs of modifying locomotive duty cycles
are summarized in Table 27. Lifetime savings are projected for
all shut-down scenarios relative to the historical duty cycle.
If railroads have already implemented locomotive shut-down at
50°F and above to conserve fuel, these savings ($21,400) can
not be counted as part of an emission control scenario. Under
this modified duty-cycle condition, some cost ($10,300 to
$17,400; i.e., $21,400 savings for 50°F shutdown exceeds the
$4000 to $11,100 savings at 32°F) would be associated with
shut-down at temperatures just above 32°F and an effect ranging
from a small saving ($3,400; i.e., $24,800 minus $21,400) to a
cost ($11,200; i.e., $10,200 minus $21,400) could be
attributable to shut-down below 32°F.
8.2 Application of Emission Control Technology
Emissions test data on five control technologies were
presented in the literature. These data were used in Chapter 7
to develop estimates of the effects of the technologies if
applied to locomotive engines. The cost estimates for the
application of each of the five control technologies are
developed below.
Doubling of the time; i.e., halving the speed, that a
train spends in traversing a section of track as a result
of halving the power setting of the locomotives is
possible because the power required to move a train
relative to speed is dictated primarily by rolling
resistance and grade factors which tend to be linear. If
aerodynamic drag predominated in trains, as it does in
automobiles, the reduction in speed would be less than 50
percent when the power was reduced by one-half, because
aerodynamic drag does not decrease linearly with speed.
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Table 27
Summary of Costs: Duty Cycle Modification Relative to
Historical Duty Cycles
Cost per Locomotive ($)
First
Maintenance
50°F and
above
Fuel
Engine
Startability
Temperature
Under 32°F 12,200-24,800 26,500-28,500 (63,500)I/
Just above 6,900-12,000 24,000-26,000 (42,000)
32°F
(21,400)
Total
(10,200-24,800)
(4,000-11,100)
(21,400)
Limiting
high power
usage.-^
I/ Discounted at 10 percent per year over 15 year locomotive
life. Values in ( ) indicate savings.
2/ Assumes that no significant slowing of the rail system would
occur. If slowing by five percent were to occur, first cost
would be approximately eguivalent to a five percent increase in
the cost of every locomotive in service, i.e., about $50,000
with the potential for no improvement in emissions.
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8.2.1 Modification of Injector Design
Changes to the fuel injector can be expected to occur in
the number, size and location of the fuel orifices at the tip
of the injector and in changes to the sac volume. The design
and incremental manufacturing costs for a redesigned injector
is estimated to be no more than $5 to $10. For a typical 16
cylinder locomotive the cost would, therefore, be between $80
and $160. Development work leading to the optimum injector
design should not be very great and can be expected to cost on
the order of $100,000 to $200,000 for each locomotive
manufacturer. The development costs for the two manufacturers,
when distributed over locomotive production for five years
results in a per locomotive cost of between $35 and $70. The
total cost per locomotive for the use of redesigned injectors
is estimated to be between $115 and $230. Relative to the
price of a set of present design injectors ($2,500), the cost
increase represents a change of between five and nine percent.
8.2.2 Modification of Injection Timing
The design and manufacturing costs are not expected to be
large for the modified hardware necessary for the application
of a fuel injection timing schedule which is different from
that presently used. This component of the total cost of
changing fuel injection timing can safely be estimated as being
no more than $100 per locomotive. The cost of development work
necessary to define the optimum injection timing can, however,
be expected to be significant because of the tradeoffs which
will have to be made between each emission specie (HC, CO, NOx,
and particulate or smoke) as well as fuel economy. These
development costs can be expected, therefore, to be similar to
but somewhat lower than those for the development of a cylinder
head for use with glow plugs. The cost per locomotive is,
therefore, estimated to be between $200 and $300 when the
development costs are spread over five years of production.
The total cost per locomotive for the application of retarded
injection timing is projected to be in the range of $300 to
$400. Relative to the $10,000 to $12,000 price of the fuel
injection pumps and injectors used on locomotives, these costs
represent a change of between two and four percent. The
lifetime cost for the 1-2 percent fuel economy penalty is
estimated to be between $8,000 and $16,000.
8.2.3 Exhaust Gas Recirculation
Successful application of exhaust gas recirculation (EGR)
to locomotive diesel engines will require resolution of
problems associated with the design and development of the EGR
system as well as problems of engine durability associated with
the use of EGR on these engines.
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The readily identifiable problems or questions which will
require resolution prior to the successful application of EGR
to locomotives are: 1) the choice between the use of either
cooled or uncooled exhaust gases for recirculation, 2) the
degree to which particulate matter is removed from the gases
which are to be recirculated, 3) the location for the
introduction of the recirculated exhaust gases into the engine
intake system, and 4) the methods for either reducing or
eliminating the deleterious effects of exhaust gas
recirculation on engine durability. These factors are
discussed briefly below with the objective of identifying a
representative system design.
Data in Reference 3 does not show a substantial difference
between the effectivenesses of cooled and uncooled EGR in the
control of NOx emissions. On this basis, it appears that the
less costly, uncooled EGR method could be selected by
locomotive manufacturers. One locomotive manufacturer
expressed the opinion, however, that cooled EGR would be
required to maximize the benefits of EGR while avoiding thermal
problems in the engine which may be associated with uncooled
EGR.
Considerations of engine durability and particulate matter
removal are interrelated and will be treated here as a single
entity. Particulate material contained in the exhaust gases of
diesel engines, if recirculated, can cause accelerated wear in
the engine, deposit build up in the engine intake system
downstream of the point of EGR admission and contamination of
the lubricating oil. Reductions in the amount of particulate
materials which is recirculated should reduce the deleterious
effects of EGR. Two approaches could be considered for
reducing the amount of particulate material which is
recirculated. These approaches are the application of a
cyclone separator where the heavier and/or larger particles are
separated from the gas stream or the use of filters which trap
the particulate material. The advantage of the cyclone
separator approach is that it is self cleaning and requires
little maintenance. Its disadvantage lies in its inability to
remove the smaller and/or lighter particles. As a consequence,
the smaller particles will pass through the separator and would
be admitted into the engine. The advantage of the filter
approach is its ability to remove much of the fine particulate
material. The disadvantage of the filter approach is the rapid
plugging of the filters and the subsequent need for the
addition of an automatic process for cleaning or regeneration
of the filters. Because of the established long term
reliability of operation of cyclone separators versus a
filtering approach, manufacturers can be expected to view the
cyclone separator as the preferred first approach. (Successful
development of filters for use on heavy-duty diesel engines
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applied to road vehicles coupled with transfer of this
technology to locomotives could result in the displacement of
cyclone separators as the preferred approach.) The use of
filters may be viewed as a fall back position if engine
durability proved to be unacceptable because of inadequate
removal of fine particulate material by a cyclone separator and
if the application of other methods of increasing durability
proved to be inadequate. Methods for increasing engine
durability are expected to include improvements in lubricant
filtration and changes in the metallurgy and/or surface finish
of such components as cylinder liners, piston rings, camshaft
and tappets, bearings and journals and valve stems and valve
guides.
Factors bearing heavily on the selection of the point for
admission of the EGR into the engine intake system are the
effects of deposits on components of the intake system (100
percent particulate removal is not achieved by either
particulate removal system) and the requirements for delivering
the recirculated gases to the engine intake. If the
recirculated exhaust gases were introduced before the
turbocharger, deposit build-up would be expected to occur
throughout the engine intake system including the compressor
section of the turbocharger, the intercooler, and the intake
air preheater (if used as a starting aid). The accumulated
deposits would degrade the performance of these components.
The volumetric capacity of the turbocharger would also have to
be increased to compensate for the temperature increase and
consequently volumetric increase of the gas (air plus exhaust)
being supplied by the turbocharger. Because of the small
positive pressure differential which exists between the gas in
the exhaust manifold and the entry of the turbocharger
compressor section, pumping of the exhaust gases into the
intake manifold could probably be avoided. If the recirculated
exhaust gases were introduced downstream of the compressor,
intercooler and air preheater, the performance of these
components would not be degraded. Pumping of the recirculated
gases into the intake manifold would, however, be necessary
because of the high pressure in the intake manifold.
Manufacturers could reasonably be expected to introduce the
recirculated exhaust gases downstream of the compressor,
intercooler and air preheater because this location would avoid
degredation of the performance of those components.
The configuration of an EGR system for a locomotive engine
can, therefore, be expected to be as follows; a compressor to
raise the pressure of the gas being recirculated, a turbine for
driving the compressor, a cyclone separator, a flow control
valve, a flow control valve actuator and its control system,
and plumbing between the system components. The compressor and
turbine for pumping the exhaust gases into the intake manifold
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would be similar to a turbocharger and can, as a first
estimate, be expected to cost between 15 and 20 percent of that
of the locomotive engine turbocharger. With a price range of
between $25,000 and $30,000 for a turbocharger, these
percentages correspond to a cost of between $3,000 and $6,000.
The per locomotive cost of the components of the EGR system,
including redesigned exhaust and intake manifolds is expected
to be in the $8,000 to $15,000 range. The incremental cost of
the improved lubricant filtration system and modified (design
and metallurgy) cylinder lines, rings, bearings, and valve
train is estimated to be between $1,000 and $1,500 per
locomotive. The costs for the development of a marketable EGR
system and the associated engine modifications would be higher
than those for a cylinder head modification but lower than
those for a major redesign to accommodate the use of
antifreeze. The cost is, therefore, estimated to be on the
order of $5,000,000 to $10,000,000 for the two manufacturers.
When spread over a five year production period, these costs
would represent a per locomotive cost of between $850 and
$1,700. Increases in the cost of maintenance should not be
large and would be attributable primarily to increases in the
cost of lubricant filtration. A reasonable cost for this
maintenance would be between $500 and $1,000 spread over the
lifetime of the locomotive. The lifetime cost for the 1
percent fuel economy penalty is estimated to be $8000. The
total projected cost per locomotive associated with exhaust gas
recirculation is, therefore, between $21,350 and $33,200.
8.2.4 Reduced Scavenging (Increased Internal Exhaust Gas
Recirculation)
The purpose of the emission control approach addressed in
this sub-section is the dilution within the engine cylinders of
the fresh air charge for each power stroke with some of the
exhaust gases from the previous power stroke. Dilution of the
intake air with exhaust gases is achieved by the retention of
some of the exhaust gases in the cylinder. In the EMD 2-stroke
engines, removal of the exhaust gases from the cylinder can be
viewed as a two step procedure. The first step is the opening
of the exhaust valves which allows venting of the relatively
high pressure gases through the valves. The second step is the
opening of the intake ports which allow the pressurized intake
air to enter the cylinder and blow the remaining exhaust gases
out of the cylinder through the open exhaust valves. This
second step is referred to as scavenging. Reducing the amount
of scavenging which occurs could be accomplished by three
methods; i.e., either by earlier closing of the exhaust valves,
by reducing the pressure of the intake air or by a combination
of the two previously identified methods. In 4-stroke engines
which are used by GE, removal of the exhaust gases can be
viewed as a three stage procedure. The stages are the opening
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of the exhaust valves which allows venting of the relatively
high pressure gases, displacement of gases in the cylinder
through the exhaust valves by the piston as it rises in the
cylinder and some scavenging of the combustion chamber by
pressurized intake air during the short period that both the
intake and exhaust valves are partially open. The period while
both the intake and exhaust valves are partially open is
referred to as the valve overlap period. On a 4-stroke engine
which is turbocharged (intake air is pressurized) the amount of
exhaust gas which is retained can be increased by either
reducing the pressure of the intake air or by reducing the
valve overlap. In a nonturbocharged engine which operates at
the low speeds typical of locomotive engines, an increase in
valve overlap achieved by earlier opening of the intake valve
would be one method of increasing the quantity of exhaust gases
which are retained.
In the experimental work on reduced scavenging reported in
the literature, the desired objective was achieved by bleeding
intake air out of the intake manifold. While this approach is
suitable for use in an experimental program, it is not judged
to be appropriate for use on production locomotives. On
production locomotives, increasing the amount of exhaust gas
which is retained would probably be achieved through changes in
the timing of the valves or through changes in the air delivery
characteristics of the turbocharger.
Both of these approaches would require development work to
define the changes required and some small increase in the
manufacturing cost of the redesigned parts to cover changes in
production tooling. Development costs per manufacturers of
$250,000 to $500,000 should be sufficient for these changes.
This cost would translate into a per locomotive cost of between
$80 and $170. Adding a cost of between $40 and $50 per
locomotive to cover manufacturing costs results in a total cost
estimate of between $120 and $220 per locomotive. Maintenance
costs should not be affected by this approach to the control of
exhaust emissions. The lifetime cost for the 1 percent fuel
economy penalty is estimated to be $8000.
8.2.5 Water Injection
Two procedures can be considered as offering potential for
introducing water into the combustion chambers of a locomotive
engine. The procedures are: 1) the spraying of the water into
the intake system of the engine, and 2) the formation of a
water/fuel emulsion which is injected into the combustion
chambers by the fuel injection system. Some basic
considerations pertaining to the use of water injection are
discussed below prior to the development of an estimate of the
cost of water injection for a locomotive engine.
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Fundamental to either method for the introduction of
water, is the need to provide a tank on the locomotive for
storage of the water. References 3 and 4 showed that the water
injection rate should be about 75 percent of the fuel injection
rate. With this water injection rate, a water storage tank
volume of about 2,250 gallons would be required to correspond
to the 3,000 gallon fuel tank which is most commonly used.
Locomotive fuel tanks occupy essentially all of the space
between the trucks (wheel, motor assemblies) of the locomotive
and extend the full width of the locomotive. Dimensionally,
the fuel tanks are about 9 feet wide, 3 feet deep and 16 feet
long. The dimensions for a water tank which would hold the
required volume of water would be about 9 feet by 3 feet by 12
feet. Presently, there does not appear to be even a small
portion of this space requirement available on locomotives.
Reducing fuel volume is not considered to be a viable option
for securing space for water storage because the present volume
of fuel will support full power operation for no more than
about 16 to 20 hours and railroads are already expressing a
desire for additional fuel volume. Increasing the size of the
locomotive to accommodate the water tank also does not appear
to be a viable alternative. Width and height increases are not
possible because of clearance requirements between locomotives
on parallel tracks and in tunnels. Any increase in the length
of a locomotive would be limited to the difference between the
present length of the locomotive and the maximum length as
defined by the minimum radius of the turns in the track on
which the locomotive must operate. Locomotive manufacturers
indicate that locomotives are already as long as is possible
within the constraints of the tracks on which they will be
operated. At this time, the addition of a tender to each
locomotive appears to be the only option whereby the necessary
water tank volume could be provided.
Two other factors which would impact the use of water
injection on locomotive engines are the weight increase of the
locomotive and the availability of water of appropriate
purity. Locomotive axle loading is limited to 70,000 pounds
because of the load carrying limitations of the track, Loads
imposed on the track by each axle of a fully fueled and
operational locomotive are presently on the order of 65,000
pounds or higher. There is, therefore, very little load
carrying reserve capacity available. If the use of a tender
were adopted, the weight constraints would be eliminated
because the weight of the tender would be supported by a
separate set of wheels.
The other factor which has been identified by locomotive
manufacturers as a source of concern with respect to the use of
water injection is the availability of pure water. Use of
water which contains dissolved minerals, so called hard water,
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in the water injection system would result in the formation of
deposits in the water delivery system, the combustion chambers,
the exhaust system and on the turbocharger of the locomotive
engine. Deposit formation on the system components must be
avoided because of resulting degradation in the performance of
the locomotive and of the water injection system. The
formation of deposits can be controlled by the use of
contaminant free water. The cost of facilities to produce
water of the necessary purity plus the distribution and storage
of the water at each refueling point are estimated to be
equivalent to about a one percent increase in the cost of fuel,
i.e., approximately $8,000 during the lifetime of a locomotive.
If it is assumed that a water tender would be employed
with each locomotive, the cost of the water injection system
would consist of the tender, the water delivery and metering
system and a system to prevent freezing of the water. The cost
of the tender is estimated to be between $20,000 and $40,000
and would include a diesel fueled heater system to prevent
freezing of the water. Introduction of the water into the
combustion chambers may be achievable by either of the
following methods. The first method for water delivery would
be through the formation of a fuel-water emulsion which would
be injected into the cylinders by a suitably modified fuel
injection system. The hardware components of this system would
be pumps and flow control valves for the delivery of the fuel
and water to the emulsifier, the emulsifier, modified fuel
injection pumps and injectors, a modified fuel return line
which carried unused fuel and water back to the emulsifier and
a fuel tank heater to control fuel waxing (waxing is presently
controlled by the return of warmed fuel to the fuel tank) . The
cost for this approach can be expected to be between $10,000
and $15,000 per locomotive including development costs.
The second method for accomplishing water injection would
be through the introduction of the water into the intake air
stream. On the 4-stroke engines produced by GE this could be
accomplished by the continuous introduction of water
immediately upstream of the intake valves. Including
development costs, the cost of the continuous flow system is
estimated to be between $3,000 and $5,000 per locomotive. On
the 2-stroke engines produced by GM, timed water injection
would appear to be necessary so as to avoid puddling of the
water in the intake manifold. For the timed system, the cost
is estimated to be about $2,000 higher or between $5,000 and
$7,000 per locomotive.
Because the cost of introducing water into the intake air
is expected to be lower than the cost of the water-fuel
emulsion system, it would appear that it could be the preferred
system. There are, however, presently unanswered questions
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pertaining to the successful control of corrosion in the engine
associated with the introduction of the water into the intake
air which may make this system impractical. The estimated
total cost per locomotive of a water injection system could be
between a low of $23,000 where the water is injected into the
air entering the engine and a high of $55,000 with an emulsion
system plus an annual cost for water of about $1,000. Lifetime
costs are projected to be between $31,000 and $63,000. Because
of problems inherent to the use of water injection as an
emission control concept for locomotives (addition of a tender,
freeze protection, providing and distributing water of adequate
purity and corrosion control) it must be viewed as an approach
with little practical potential.
For ease of reference, the estimates of the costs of the
five emission control technologies are summarized in Table 28.
8.3 Cost-Effectiveness
The financial efficiency of an emission control strategy
can be measured by developing the ratio of the costs incurred
to the benefits realized. This ratio is referred to as the
cost-effectiveness of the control strategy and is usually
expressed in terms of lifetime costs and lifetime benefits for
the equipment involved.
The effects on emission rates and on fuel consumption of
the control strategies which were analyzed previously are
summarized in Table 29. These values are based on historical
locomotive duty cycles. Since there are no data upon which to
base an estimate of the extent to which railroads have taken
advantage of the shutdown capability of recent design
locomotives, i.e., implemented locomotive shut-down at 50°F and
above as a fuel conservation measure, no attempt was made to
estimate benefits under revised duty cycles. Lifetime changes
in the mass of emissions contributed by an average locomotive
within AQCRs and the change in fuel consumed by an average
locomotive over the 15 year locomotive lifetime are shown in
Table 30. For each control strategy and pollutant, the values
shown represent the change relative to historical duty cycles.
The costs which have previously been developed are
summarized in Table 31. Fuel and maintenance costs are
discounted to the year that an appropriately modified
locomotive is placed in service. Combining the costs and
emission benefits results in the cost-effectiveness values for
each control procedure as shown in Table 32. In the case of
the engine shutdown options, total costs (savings) are equally
divided between HC, CO, and NOx in determining the
cost-effectiveness values. In the cases where emission control
hardware is employed, costs are equally divided between the
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Table 28
Summary of Costs:
Application of Emission Control Technology
Cost Per Locomotive ($)
Technology
Modified Injectors
Modified Injection Timing
Exhaust Gas Recirculation
Reduced Scavenging
Water Injection
First
Operating &
Maintenance
115-230 0
300-400 0
12,850-24,200 500-1,000
120-220 0
23,000-55,000 8,00o!x
Fuel!7
Total
0 115-230
8,000-16,000 8,300-16,400
8,000 21,350-33,200
8,000 8,12.0-8,220
0 31,000-63,000
I/ Lifetime cost discounted at annual rate of 10 percent.
2_/ Approximately one percent of the lifetime cost of fuel consumed discounted at 10
percent per year.
-------
Table 29
Percent Change in Lifetime Emissions and Fuel Consumption
By Control Procedure Relative to Historical Duty Cycles
Control Procedure
Engine Shut-down
HC
0 below 32°F -17
0 at 33°F and above -10
0 at 50°F and above - 5
Eliminating high power
settings
Injection Timing Retard 0
Modified Injectors
EGR
Reduced Scavenging
Water Injection
Emissions (%
CO
-13
- 8
- 4
2/
+20
change )
NOx
- 7
- 4
- 2
-25
-20 -20 +25
-20 +200 -45
0 +200 -10
+10 -5 -15
I/ N.A. - effect could not be estimated from the data
{expected to be very small).
2/ Significant uncertainties with the practicality of
Fuel
Consumption
Smoke (% Change)
N.A.V - 8
N.A. - 5
N.A. - 3
+50 +1 to +2
0 0
+200 to +700 +1
+200 +1
0 0
this system makes its
use questionable. Values were, therefore, not presented.
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Table 30
Lifetime Change in Mass of Emissions in AQCRs
and Fuel Consumed For an Average Locomotive
Relative to Historical Duty Cyclesl/
Control Procedure
Engine Shut-Down
"below 32°F
°at 33°F and above
°at 50 °F and above
Injection Timing
Retard
Modified Injectors
EGR
Reduced Scavenging
Water Injection
HC (tons)
-6.4
-3.8
-1.9
0
-7.5
-7.5
0
+3.8
CO (tons)
-9.2
-5.7
-2.8
+ 14.2
-14.2
+71.1
+71.1
-3.6
NOx (tons)
-26.0
-14.9
-7.4
-93.0
+ 93.0
-167.3
-37.2
-55.8
I/
Fuel (1,000 gal)
-120.0
-75.0
-45.0
+ 30.0
0
+ 15.0
+ 15.0
0
Derived from emission rates and fuel consumption values in Chapter 5. An average
locomotive is defined as 20% of a switch and transfer locomotive and 80% of a
line-haul locomotive (derived from the 3.93:1 ratio for line-haul to switch and
transfer locomotives.)
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Table 31
Lifetime Costs for Emission
Control Procedures per Locomotive
Relative to Historical Duty Cycles
Control Procedure Purchase Price Maintenance!'
($1000) ($1000)
Fuel!7
($1000)
Engine Shutdown
0 32°F and below 12.2 to 24.8 26.5 to 28.5 -63.5
Total
($1000)
-24.8 to -10.2
0 at 33°F and
above
6.9 to 12.0
24.0 to 26.0
-42.0
-11.1 to -4.0
at 50°F and
above
-21.4
-21.4
Injection Timing
Retard
Modified
Injectors
EGR
Reduced
Scavenging
Water Injection
0.3 to 0.4
0.1 to 0.2
12.9 to 24.2
0.1 to 0.2
23.0 to 55.0
8.0 to 16.0
0.5
0
to 1.0
0
8.0
0
8.0
8.0
0
8.3 to 16.4
0.1 to 0.2
21.4 to 33.2
8.1 to 8.2
31.0 to 63.0
I/ Values given for maintenance and fuel costs are discounted costs to the year that
the modified locomotive is produced. The discount rate used is 10 percent per
year. Fuel cost of $1 per gallon is assumed. Values proceeded by a negative
sign are savings.
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Table 32
Cost Effectiveness of Control
Strategies Based on Historical Duty Cycles!/
Cost Effectiveness ($/ton)
Control. Procedure
HC
CO
NOx
Engine Shut-Dovn
"below 32°F (1,290) to (755) (900) to (530)
°at 33°F and above (975) to (700) (650) to (480)
°at 50°F and above
Injection Timing
Retard
Modified Injectors
EGR
Reduced Scavenging
Water Injection
(3,755)
8 to is!/
1,425 to l,765l/
(2,550)
4 to 8!/
(320) to (185)
(250) to (180)
(965)
85 to 175l/
65 to 9 5l/
220I/
4,305 to 8,750£/ 280 to 565&/
I/ Numbers in ( ) indicate savings rather than costs.
Costs are equally divided between the pollutants which are
reduced by the control procedure.
2/ Injection timing retard reduced NOx while increasing smoke and
CO and with minimal impact on HC.
3/ Modified injectors reduced HC and CO, increased NOx without
affecting either CO or smoke.
4/ EGR reduced HC and NOx, increased CO and smoke.
5/ Reduced scavenging reduced NOx, increased smoke and CO without
affecting HC.
6/ Water injection reduced CO and NOx, increased HC and did not
affect smoke.
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pollutants which would be reduced through the application of
the control technology. Another method of calculating the
cost-effectiveness would be to assign the total cost of the
emission control technology to the pollutant which the
technology is primarily designed to control. For example, EGR
would be applied for the control of NOx and the HC benefit
could be treated as being free rather than distributing the
costs equally between HC and NOx as was done in Table 32. If
this were done, the cost-effectiveness value for HC would be
zero and the value for NOx would be doubled to between $130/ton
and $190/ton. It should be noted that the application of a
technology which reduces one pollutant may result in an
increase in one or more of the other pollutants, e.g., NOx and
HC emissions were reduced by EGR, but smoke and CO emissions
were increased (see Table 29). (Note that none of the
technologies for which data were available showed any benefits
with respect to the control of smoke (particulate) emissions
(Table 29)). The true costs and, therefore, the cost-
effectivenesses of technologies which produce adverse effects
would have to be increased to cover the application of
additional technologies which would neutralize some or all of
the penalties. For example, the cost-effectiveness of control
of HC emissions through the use of modified injectors is 8 to
15 dollars per ton (Table 32) but with an accompanying increase
in NOx emissions. If it were to be assumed that an increase in
NOx emissions could not be accepted but that an increase in
smoke emissions could be accepted, then combining injection
timing retard and modified injectors (Table 29 shows a
canceling of the effects of these technologies on NOx
emissions) could result in an acceptable procedure. The
cost-effectiveness value for the control of HC emissions would
then be between $885/ton and $2215/ton (cost of both
technologies (Table 31) divided by HC benefits from modified
injectors (Table 30)).
Examples of the cost-effectiveness of controlling HC, CO,
and NOx emissions from other sources are shown in Table 33 for
purposes of comparison. Comparing the cost-effectiveness
values for locomotives, by control procedure, with those for
other sources shows that the cost-effectiveness of control for
locomotives is not excessive. Combining emission control
technology procedures to limit or change the area of a negative
effect, as was done in the example above, may result in
substantial change in the cost-effectiveness values.
Combinations of emission control technology and engine shutdown
capability could, however, result in the reduction in emissions
at a net savings because of the reductions in fuel consumption.
It is appropriate to note at this point that there were no
data on emission control technologies for the control of smoke
emissions and that cost and cost-effectiveness estimates for
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Table 33
Cost Effectiveness for Controlling Non-Locomotive Sources
Control Strategy
LDV, statutory standard
LDV, 1/M
LDT, statutory standard
Industrial Boilers - Coal Fired
Industrial Boilers - Gas & Residual
Oil Fired
Coke-ovens (80% HC reduction)
HDGE, evap. control (evap, 5.8 to 0.5)
Motorcycle standards
Cost Effectiveness ($/ton)
HC CO NOx
508l/
943I/
207I/
49Q2/
112I/
616I/
44l/
57l/
130 to
15002./
500 to
14002/
I/ "Revised Gaseous Emission Regulations for 1985 and Later
Model Year Heavy-Duty Engines," U.S. EPA, QMS, ECTD, July
1983.
2/ Federal Register, June 19, 1984, 49 FR 25144 and 49 FR 25145.
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the control of smoke emissions are not included. Incorporation
of a technology which would either negate the smoke emission
penalties caused by other technologies or which would reduce
smoke emissions could result in a change in the
cost-effectiveness values which are shown.
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9.0 EXISTING STATE AND LOCAL REGULATIONS
This portion of the report addresses "the status and
effect of current and proposed state and local regulations
affecting such emissions," i.e., Section 404(a)(3).
To fulfill the requirements, the study evaluated the
status and effects of the subject regulations in the following
manner. First, the relevant regulations were compiled from
political jurisdictions (subdivisions) across the nation.
Second, the regulations were evaluated to determine their
effects on: 1) health and welfare, 2) application of
operational and technical controls to railroad emissions
sources, and 3) interstate commerce.
A review of the literature showed that although at least
one study (Sturm, 1973) had documented a number of typical
state and local regulations, there was no existing compilation
or evaluation of the effects of the standards which would be
useful to this study.
The majority of information used in this analysis was
obtained from a survey of the 50 states and 229 local (i.e.,
regional, county, and city) air pollution control agencies. The
address of each office was obtained from the Directory of
Governmental Air Pollution Control Agencies (APCA, 1975). The
questionnaire requested three types of information: 1) all
current and proposed regulations which pertain to or could be
construed to pertain to locomotives, 2) any problems with
enforcement which they may have encountered, and 3) opinions as
to whether there was a need for Federal regulations.
State laws which incorporated specific language as to the
level of control were obtained directly from the statutes. The
remaining information came from the diesel-electric locomotive
manufacturers, the Association of American Railroads, railroad
companies, and the Department of Transportation.
9.1 Survey of Existing Regulations
9.1.1 Survey Returns
Of the 279 governmental air pollution control agencies
surveyed, a total of 308 separate replies were received. The
additional responses are accounted for by the fact that some
questionnaires were sent to regional authorities which had
several city or county members within the region. In these
cases, the region's response was tabulated for each individual
subdivision. Responses were received from 92 percent of the
279 requests, as tabulated in Table 34.
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Table 34
Survey Returns
Control
Authority
State
Local
Total
Total
Recruests
50
229
279
Total
Responses
47
207
254
Percent
Return
90
94
92
Jurisdictions
Represented
47
261
308
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The compilation of emission regulations by this study
should be viewed as being a reasonable documentation of the
existing approaches and not a complete bibliography in itself.
It represents a best effort at cataloging responses which were,
at times, incomplete and fragmentary. All of the submitted
material was reviewed and, in some cases, regulations which
could be construed to include railroad rolling stock were
identified in addition to those pointed out by the
respondents. If an incomplete text of the regulations was
included, it is possible that some standards were mistakenly
included or excluded because of a lack of other relevant
details. Also, as a compromise in the length of this analysis,
the regulations were condensed and this may have unavoidably
added some ambiguity.
9.1.2 Types of Regulations
Two types of state and local regulations were found which
pertained to railroad rolling stock: gaseous and particulate.
The vast majority of the regulations pertained to particulate
emissions. The gaseous emissions were defined in terms of
specific chemical pollutants (HC, CO, NOx, and SO^) and
odor. None of these regulations specifically cited permissible
emissions rates, but instead made it illegal for the emissions
to create a nuisance. The nuisance regulations that pertained
to excessive odor were not cataloged.
The particulate regulations almost exclusively pertain to
visible smoke emissions, with only a very small number citing
specific emission rates.
Visible smoke standards define allowable emissions in
terms of an acceptable percent opacity or Ringelmann number.
In many cases, the standard is expressed by both measurements.
The percent opacity is defined as that fraction of light
transmitted from a source which is prevented from reaching the
observer or instrument receiver. The Ringelmann scale was
developed by the U.S. Bureau of Mines as a measurement for
black and white smoke. As originally developed, Ringelmann ttl
was to equal 20 percent opacity, Ringelmann 82 equals 40
percent, #3 equals 60 percent, #4 equals 80 percent, and tt5
equals 100 percent.
9.1.3 Typical Regulation
Regulations imposed by the State of Illinois are presented
as an example of typical regulations. The regulation provides
that:
"Rule 707. Diesel Engine Emission Standards.
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707(a) The visible emission standard in Rule 706 shall not
apply to diesel engines.
707(b) With the exception of Rule 707(e) diesel engines
manufactured before January 1, 1970, shall not be operated
in such a manner as to emit smoke which is equal to or
greater than 30 percent opacity except for individual
puffs of smoke. Individual puffs of smoke shall not
exceed 15 seconds in duration.
707(c)(l) Diesel engines shall be operated only on the
specific fuels as specified in the engine manufacturer's
specifications for that specific engine, or on fuels
exceeding engine manufacturer's specifications.
707(c)(2) Persons liable for operating diesel engined
fleets wholly within S.M.S.A. shall furnish to the
Technical Secretary of the Illinois Air Pollution Control
Board once each year, proof that the fuel purchased and
used in their operations conforms to Rule 707(c)(l).
707(d) All diesel engines operated on public highways in
Illinois coming from out of the State shall conform to
Rule 707(b).
707(e)(l) No person shall cause or allow the emission of
smoke from any diesel locomotive in the State of Illinois
to exceed 30 percent (30 percent) opacity.
707(e)(2) Rule 707(e)(l) shall not apply to:
(A) Smoke resulting from starting a cold locomotive, for
a period of time not to exceed 30 minutes.
(B) Smoke emitted while accelerating under load from a
throttle setting other than idle to a higher throttle
setting; for a period of time not to exceed 40 seconds.
(C) Smoke emitted upon locomotive loading following
idle; for a period of time not to exceed 2 minutes.
(D) Smoke emitted during locomotive testing,
maintenance, adjustment, rebuilding, repairing or breaking
in; for an aggregate of 10 minutes in any 60-minute period.
(E) Smoke emitted by a locomotive which because of its
age or design makes replacement or retrofit parts
necessary to achieve smoke reduction unavailable. These
locomotives shall be retired at the earliest possible
time."
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In states where there are marked differences in altitude,
there are sometimes different standards depending upon
altitude, e.g., below and above 5,000 feet.
9.1.4 Compilation of State and Local Standards
The stated applicability of the regulations varied from
very specific to very broad. In general, the regulations were
expressed in terms of steady-state emissions with specific
exceptions (Table 35). The following definitions were used in
compiling and categorizing the state and local regulations:
1. Stated applicability of the regulation to:
a. Locomotives: Usually specific to railroad industry
diesel-electric locomotives, but may include steam-powered
locomotives and amusement park operations as well.
b. Generic Description: Includes all sources within a
general description class, e.g., internal combustion engine,
diesel engine, motor vehicle, mobile source. This category may
include locomotives, locomotive diesel engines, refrigerator
cars, and other railroad rolling stock.
c. Emissions into the Atmosphere: This category
contains the most inclusive of the regulations that
specifically cite allowable emission levels. A phrase such as
"maximum allowable discharge into the atmosphere from any
source" is typical of the regulatory language. When a
regulation was written to include a large variety of sources
and only incidentally mentioned railroads, the regulation was
placed into this category.
d. Nuisance: An all-inclusive category for any
emission which "causes or contributes to the condition of
pollution." Because of its vagueness, this type of regulation
is seldom enforced.
2. Exceptions
a. Excursions: This is a general category which limits
temporarily excesses of the continuous standard in duration and
intensity.
b. Maintenance: These exceptions apply when the source
is being repaired, adjusted, or rebuilt.
c. After Idle: Higher allowable emission levels
following a prolonged period of idle may be necessary due to
below normal operating temperatures or carbon loading.
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Table 35
Categorization of State and Local Regulations
Applicability of Regulations
Exceptions to the Rules
Subjective Evaluation
No
Regulations
Stnte
Level
Local
34%
39%
(16)
(101)
Generic
Locomotive Description
21%(10) 30%(14)
10%(27) 18%(48)
Emissions
Into
Atmosphere
34%(16)
28%(73)
Nuisance
4%(2)
13%(35)
After Cold
Excursions Maintenance Idle Start Other
57%(2) 19%(9) 17%(8) 19%(9) 11%(5)
42%(110) 4%(10) 5%(12) 8%(20) 4%(10)
Enforcement
Problems
Yes
8%(2)
15% (19)
NO
92%(23)
85%(105)
Need for
Federal
Regulation
Yes
74% (26)
84%(114)
No
26%(9)
16%(22
Level
I
1'
o
I
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d. Cold-Start Smoke: Refers to the blue-white smoke
resulting from cold combustion chambers.
e. Other: This category contains exceptions which are
not covered by the other classifications.
From the list of definitions it should be clear that
emission standards for categories other than "Locomotive" are
included if: 1) they may be construed to include locomotives,
or 2) they may limit emissions from secondary rolling stock.
For example, when the generic classification referred to
diesel-powered vehicles or motor vehicles, the standard for
emissions into the atmosphere was included to account for
secondary rolling stock.
Survey answers with regard to current enforcement problems
and the need for Federal preemptive standards are cataloged
under the headings entitled "Enforcement Problems" and "Federal
Regulations," respectively (Table 35).
9.1.5 General Results
The results of the survey are summarized in Table 35. The
percentages are based on the total number of responses to each
of the three questions. The number of cases upon which the
percentage was calculated is included to gualify the figure.
The percentiles listed under the "Applicability of Regulations"
and "Exceptions to the Rules" categories do not total 100 since
some political jurisdictions have more than one relevant
standard.
The basic state laws are clean air acts, enacted in
response to the Federal Clean Air Act of 1967. Almost all
states have sections in their laws which either directly
mention locomotives or could be construed to include
locomotives and secondary railroad rolling stock. Three states
have a Ringelmann or opacity standard in the law: Maine,
Kentucky, and California. Most states, however, authorize the
state air pollution control agency to develop suitable
standards.
Of the state air pollution control authorities that
responded, 66 percent or 31 had a steady-state standard which
applied to railroad rolling stock. No states had a nuisance
standard only.
For local air pollution control authorities, 60 percent or
156 had a suitable steady-state standard. Eight percent or 21
had a nuisance standard only; therefore, 52 percent or 135
localities had what might be termed a readily enforceable
regulation.
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There is no interstate or intrastate consensus as to the
most appropriate level of control among the air pollution
authorities that do have regulations. Minnesota controls
locomotives to 10 percent opacity, while Iowa controls them to
40 percent. California's standard is Rtt2 or 40 percent
opacity, but in San Francisco it is Rttl or 20 percent opacity.
The exceptions to the regulations are also inconsistent.
There is no consistency with regard to the authorized
regulatory agency. Some states, Maryland and Texas for
example, preempt local control, although localities can and do
adopt and enforce the state regulations. Some states (e.g.,
Michigan, Kansas and Ohio), have no state regulations, but
individual localities do. In most states, there are both state
and local regulations.
Several of the respondents exhibited confusion with regard
to the authority for regulating this source. Some county air
pollution control agencies in California claimed that the state
had preempted local railroad regulations, while others had
regulations which they were enforcing. (There was also some
confusion as to whether locomotives were mobile or stationary
sources.) A county in Maryland indicated they thought the
Clean Air Act had already preempted other standards and
assigned regulatory authority to the Department of
Transportation or EPA.
Preemption was not the only reason why some air pollution
control agencies did not have regulations. These reasons are
listed below:
1. Railroad operations do not draw citizen complaints
or the number of complaints is inadequate to justify regulatory
action;
2. Only stationary sources are controlled;
3. The appropriate state enabling legislation does not
exist; and
4. There are no railroads (Hawaii).
Minnesota has the only regulation that apparently excludes
a portion of the railroad rolling stock. All 2-cycle engines
are specifically exempted from meeting the regulatory
requirements. The majority of diesel-electric locomotives and
perhaps all of the diesel-powered secondary rolling stock are,
however, 2-cycle engines.
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9.1.6 Subjective Questions on Enforcement
Of the respondents that had applicable regulations, there
were varying degrees of enforcement ranging from essentially no
enforcement to strict enforcement. The reasons given for low
levels of enforcement were:
1. No citizen complaints;
2. Other sources are more important;
3. A general lack of time and money, although a
definite need for control may have existed; and
4. Enforcement only on citizen complaints, but no real
active program.
There was no correlation between the specificity of the
regulation (i.e., a locomotive standard being the most
specific), and the degree to which it was enforced, excluding
those classified as nuisance. California and its localities
actively enforce their "emission into the atmosphere" standard
against railroad rolling stock.
It was extremely difficult to draw any conclusion from the
survey with respect to enforcement problems. Many states and
localities indicate they did not consider railroads to be a
major problem, did not try to enforce any regulations they
might have, and obviously did not think enforcement was a
problem. Other localities did enforce their regulations, but
found a great deal of cooperation from the railroads, and also
did not consider enforcement a problem. The standard
enforcement procedure was for the agency to send a letter to
the railroad stating that Unit XXX was seen (means visible
smoke) at a certain time in a certain place in violation of the
regulations, and requested that the railroad rectify the
problem. The railroad, in a return letter, would report the
steps it had taken to end the emissions. Invariably, the
problem, as reported by the railroads, was a malfunctioning
part. Most agencies did not have a way to confirm the
railroad's report and accepted the report at face value.
Eight percent or two of the 25 states definitely had
trouble enforcing their regulations: Maine and Oregon.
Fifteen percent or 19 out of 124 localities experienced
difficulties. These results must be viewed with some
reservations, however, since all of the respondents did not
address the question and railroad emissions were not generally
viewed as being a problem. Therefore, the only definite
conclusion that can be drawn is that at least 15 percent of the
localities responding experienced enforcement problems.
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Those who reported enforcement problems listed three main
types with two concerning the mobility of the locomotives. The
first problem is that it is difficult and/or dangerous to
follow the locomotives for long enough periods of time to
observe violations. This is particularly true where the train
runs at relatively high speeds through a countryside where the
highway does not parallel the tracks long enough for a car with
a smoke observer to follow it.
The second problem is the tendency of the railroads to
move their old, less well maintained engines from areas of
strict standards and enforcement to areas of loose
enforcement. Comments to this effect came from both areas
which were receiving the older engines, and those which
enforced strict standards and knew that the engines were being
sent somewhere else. While many areas had solved their own air
pollution problems, they knew it was a short-term solution
achieved at the expense of someone else.
The last type of problem cited was a lack of cooperation
from the railroads.
9.1.7 Subjective Questions on the Need for Federal Regulations
Of the 35 state agencies responding, 74 percent supported
Federal regulation. Of the 136 local agencies, 84 percent felt
preemption was desirable. However, these results are qualified
by the fact that about 20 percent of the state and local
agencies answering "yes," wanted a Federal standard only if the
EPA found it necessary. The responses did not distinguish
between Federal regulation of new locomotives and Federal
regulation of in-use locomotives.
Four percent and 17 percent of the state and local
agencies, respectively preferred to retain local enforcement
power under Federal standards for more effective and efficient
control.
Those that favored a preemptive standard did so mainly
because of the interstate nature of railroad operations,
stressing the difficulty of enforcing a regulation on a vehicle
which may only be within one's jurisdiction on a temporary or
occasional basis. Federal regulations could remove this
difficulty as well as preventing the transferral of locomotives
from jurisdiction to jurisdiction which some railroads now
practice.
Commenters also suggested that a preemptive standard would
resolve questions concerning the legality of state and local
regulations. Four responses included information which
explains this jurisdictional problem.
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1. A railroad company suggested that local standards do
not apply to their operations since they are engaged in
interstate commerce, and only the Federal government has
regulatory authority;
2. The court upheld the local regulation if the train
originated and terminated within local jurisdictional
boundaries, but not if it was interjurisdictional in nature;
3. The court upheld local authority to regulate
railroads for visible smoke regardless of the train's origin;
and
4. Legal precedent exists for locally regulating a
source engaged in interstate commerce based on the U.S. Supreme
Court case of Huron Portland Cement Company v. City of Detroit,
362 U.S. 440 (1960), in which the enforcement of a local smoke
standard against a vessel was contested.
Those who favored local or state standards generally had
effective enforcement, and saw no need for Federal
intervention. They also pointed to local problems, such as
large switchyards, which they thought could be better
controlled by local government.
9.2 Effects of Existing Regulations
9.2.1 Health and Welfare
This evaluation focuses on visible emissions (smoke) from
railroad sources because existing state and local regulations
do not focus effectively on gaseous emissions.
The direct impact on human health of existing state and
local regulations is impossible to assess at this time because
of lack of data on the effectiveness of state and local
regulations and because of uncertainties pertaining to the
linkage between smoke emissions and human health and welfare.
The railroad industry practice of selectively avoiding
violations for excessive visible emissions by transferring
"dirty" locomotives into areas where it is reasonably certain
no punitive action will be taken is understandable, but
undesirable. This practice of concentrating high-emitting
rolling stock in specific areas may result in concentrated
areas of emissions, but insufficient data exist to assess the
effect on health and welfare of those areas.
9.2.2 Operational and Technical Controls
Although many factors affect visible emissions from
railroad rolling stock, including the quality of fuel and
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operational practices, the two basic determinants which control
smoke are engine design and maintenance.
Diesel engines have inherent design features which prevent
a smoke free exhaust under all operating modes. However, by
optimizing the combustion chamber geometry and the fuel and air
delivery systems, smoke can be reduced. All of the currently
manufactured locomotive engines have incorporated modifications
to control much of the smoke which still plagues many of the
older engines. For this reason, excessive visible emissions
from well-maintained engines are, to a large degree, associated
with older locomotive units. The problem persists either
because low-smoke replacement parts are unavailable or, if
these parts are manufactured, they have not been installed
because of economic considerations.
Inadequate maintenance is by far the greatest contributor
to excessive visible exhaust emissions from this source. Poor
maintenance practices are a nationwide problem which persists
because the railroads find it economically attractive to defer
maintenance. It is, however, not limited to financially
distressed companies. The problem is widespread since it
affects engines regardless of their age or design
sophistication. It is characterized by maladjustment (e.g.,
fuel injection timing) and malfunctioning hardware (e.g., bad
fuel injectors or dirty air filters).
There are exceptions, however, even for well-maintained
units. Locomotives, in general, have visible emissions during
or following a period of idle because the combustion chamber
wall temperatures decrease to the point that the flame is
quenched as it nears the walls. When this happens, the fuel in
this region is not burned and these liquid hydrocarbons escape
through the exhaust system appearing as a white smoke. The
other problem, associated with line-haul locomotives, is termed
"turbocharger lag." When more power is demanded from the
engine, more fuel is added to the combustion chamber. This in
turn requires a greater amount of air for complete combustion.
However, the turbocharger, which relies on exhaust gas energy
to power it, will not gain the additional speed to supply more
air until the exhaust energy increases. Because of this period
when the turbocharger is not "up to speed" a temporary rich
mixture exists in the combustion chamber and results in black
smoke, i.e., incomplete combustion. This problem has been
alleviated to some degree by locomotive manufacturers.
Switch engines are potentially the most offensive. These
units are typically of an older design and may have been
removed from other service because of poor reliability. They
often receive no preventative type of maintenance and may be
repaired only after the higher priority line-haul locomotives.
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Switch engines undergo many throttle excursions during their
active service. - They also idle for long periods of time while
awaiting assignment. The high activity levels of these engines
plus the fact that they operate in localized areas may
predispose them to a high frequency of observation making them
a greater source of nuisance. The units, however, do not
operate strictly in switchyards, but are used in local service
train for distances often exceeding 25 miles from their home
base. These locomotives share common problems with line-haul
units although in nonnaturally-aspirated switch engines,
turbocharger lag is avoided by using a mechanically driven
roots blower. The use of this blower, however, makes a switch
engine more susceptible to excessive visible emissions at
higher altitudes where the air is less dense.
Considerable uncertainty exists in trying to estimate
future trends which might affect excessive particulate
emissions from railroad rolling stock. The cost of diesel fuel
has risen rapidly in the last decade. If this trend continues,
railroads may find it cost-effective to reduce fuel waste by
increasing attention to maintenance details. (Excessive smoke
is generally a sign of poor combustion and, therefore, poor
fuel economy.) The financial health of the industry will have
a direct affect by allowing the replacement or retrofit of
outdated equipment or necessitating the continued use of dirty
engines along with currently deferred maintenance practices.
9.2.3 Interstate Commerce
At the present time, major disruptions of interstate
commerce have apparently not resulted from the large number of
varied standards applicable to railroad rolling stock primarily
because of the widespread lack of enforcement. Some minor
problems have apparently been encountered because of different
opacity regulations. Naturally, these have occurred when rail
operations pass from a jurisdiction with lenient or nonexistent
regulations to a jurisdiction of more strict regulation or
enforcement. The best example occurs between California and
Nevada. In this area, it has been reported by government
agencies that only "clean" locomotives proceed into California
while the "dirty" units are uncoupled at the border, presumably
to service shipments moving east. Although this presents
logistics problems and time delays for the affected railroad,
it has not created any extreme adverse effects.
Although the current situation is not of immediate
concern, the potential for disruption by increased regulatory
enforcement under multiple standards poses a potential threat
to interstate commerce. It is not possible to predict the
exact degree to which rail commerce could be curtailed. It is
clear, however, that rail operations could be affected by a
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moderate increase in enforcement against line-haul locomotives
because of the multitude of different standards and political
jurisdictions.
The potential hazards of varying state and local
regulations were recognized by the railroad industry and
resulted in the request by the Association of American
Railroads for preemptive Federal emission regulations. The
request was based solely on the need to prevent disruption of
interstate commerce by removing the burden of complying with a
multitude of different standards.
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References
1. "Exhaust Emissions from Uncontrolled Vehicles and
Related Equipment Using Internal Combustion Engines, Part 1:
Locomotive Diesel Engines and Marine Counterparts," Southwest
Research Institute, Prepared for the U.S. Environmental
Protection Agency, October 1972.
2. "Railway Motive Power," Simmons-Boardman Publishing
Corporation, 1984.
3. "Assessment of Control Techniques for Reducing
Emissions from Locomotive Engines," Southwest Research
Institute, Report prepared for the U.S. Department of
Transportation and the U.S. Environmental Protection Agency,
April 1973.
4. "Locomotive Exhaust Emissions and Their Control,"
Hare, C.T., Springer, K.J. and Huls, T.A., ASTM Paper 74-D
GP-3, 1974.
5. Workshop on Diesel and Bus Engine Emissions,
Southwest Research Institute, Sponsored by Diesel and Gas Power
Division of the American Society of Mechanical Engineers, 1979.
6. "NOx Studies with EMD 2-567 Diesel Engine,"
Storment, J.D., Springer, K.J. and Hergenrother, K.M., ASTM
Paper 74-D GP-14, 1974.
7. "Studies of NOx Emissions from a Turbocharged
Two-Stroke Cycle Diesel Engine," Southwest Research Institute,
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the U.S. Environmental Protectional Agency, October 1975.
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11. Yearbook of Railroad Facts, 1980 Edition,
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12. Car and Locomotive Cyclopedia of American Practices,
1974 Edition, Association of American Railroads.
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References - continued
13. "Railroads and Air Pollution: A Perspective,"
Report No. FRA-RT-73-33, U.S. Department of Transportation.
14. "A Study of Fuel Economy and Emission Reduction
Methods for Marine and Locomotive Diesel Engines," Southwest
Research Institute, Report Prepared for the U.S. Department of
Transportation, September 1975.
15. "Train Generated Air Contaminants in the Train Crews
Working Environment," U.S. Department of Transportation, Report
No. FRA/ORD-77/08, February 1977.
16. "U.S. Coast Guard Pollution Abatement Program: A
Preliminary Report on the Emission Testing of Boat Diesel
Engines," U.S. Department of Transportation, Report No.
CG-D-21-74, November 1973.
17. Compilation of Air Pollutant Emission Factors, U.S.
Environmental Protection Agency, Publication No. AP-42, March
1975.
18. "Weather Atlas of the United States," U.S.
Environmental Data Services, June 1968.
19. Garshick E., M.B. Schenker, A. Munoz, M. Segal, T.J.
Smith, S.R. Woskie, S.K. Hammond and F.E. Speizer; 1987. A
case-control study of lung cancer and diesel exhaust exposure
inrailroad workers. Am. Rev. Resp. Dis. 135, 1242-1248
20. Garshick E., M.B. Schenker, A. Munoz, M. Segal, T.J.
Smith, S.R. Woskie, S.K. Hammond and F.E. Speizer,; 1988. A
retrospective cohort study of lung cancer and diesel engine
exhaust exposure in railroad workers. Am. Rev. Resp. Dis. 137,
820-825.
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