United States              Air and Radiation          EPA420-F-97-051
                    Environmental Protection                            December 1997
                    Agency

                    Office of Mobile Sources
SEPA        Technical
                    Highlights
                    Emission Factors for Locomotives
                    The Environmental Protection Agency (EPA) has established emission
                    standards for oxides of nitrogen (NOx), hydrocarbons (HC), carbon
                    monoxide (CO), particulate matter (PM) and smoke for newly
                    manufactured and remanufactured diesel-powered locomotives and
                    locomotive engines, which have previously been unregulated. Three
                    separate sets of emission standards have been adopted, with
                    applicability of the standards dependent on the date a locomotive is first
                    manufactured. The first set of standards (Tier 0) apply to locomotives
                    and locomotive engines originally manufactured from 1973 through
                    2001. The second set of standards (Tier 1) apply to locomotives and
                    locomotive engines originally manufactured from 2002 through 2004.
                    The final set of standards (Tier 2) apply to locomotives and locomotive
                    engines originally manufactured in 2005 and later. To analyze the
                    environmental benefits expected from these new standards, EPA had to
                    calculate emission factors for locomotives.
                    Estimated Baseline Freight Locomotive Emission
                    Rates

                    In support of the rulemaking finalizing the locomotive emission stan-
                    dards, EPA has estimated average emission rates, given in grams per
                    brake horsepower-hour (g/bhp-hr), for current uncontrolled locomotives.
                    These estimates are shown in Table 1. It is important to note that there is
                    significant variability in in-use emission rates. Table 2 shows the range
                    of emission rates that have been reported for NOx and PM.
                                                              I Printed on Recycled Paper

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Table 1 - Estimated Baseline In-Use Emission Rates
(g/bhp-hr)

Line-Haul*
Switch**
HC
0.48
1.01
CO
1.28
1.83
NOx
13.0
17.4
PM
0.32
0.44
                        * Line-haul locomotives over the line-haul duty-cycle
                         ' Switch locomotives over the switch duty-cycle
Table 2 - Range of NOx and PM Emission Rates (g/bhp-hr)
Line-Haul Cycle
NOx
10.3-18.2
PM
0.22-0.41
Switch Cycle
NOx
9.2-33.1
PM
0.22-0.86
Conversion to Gram per Gallon Emission Factors

It is often useful to express emission rates as grams of pollutant emitted
per gallon of fuel consumed (g/gal). This can be done by multiplying the
emission rates in Table 1 by a conversion factor. EPA has estimated the
appropriate conversion factor to be 20.8 bhp-hr/gal. These converted
emission factors are shown in Table 3.
Table 3 - Converted Emission Factors (g/gal)

Line-Haul
Switch
HC
10
21
CO
26.6
38.1
NOx
270
362
PM
6.7
9.2
Projected Future Emission Factors
With the new national emission standards for both newly manufactured
and remanufactured locomotives originally built after 1972, future
locomotive emission rates are projected to be much lower than the
baseline rates shown above. EPA's estimates of future emission rates for

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Tier 0-Tier 2 locomotives are shown in Tables 4-6, respectively. Table 9
gives the expected fleet average emission factors for all locomotives,
which reflects the penetration of the Tier 0-Tier 2 locomotives into the
fleet over time.
Table 4 - Estimated Controlled Emission Rates for
Locomotives Manufactured in 1973-2001 (TierO)


Line-Haul
Switch
HC
9/bhp
-hr
0.48
1.01
g/gai
10
21
CO
g/bhp
-hr
1.28
1.83
g/gai
26.6
38.1
NOx
g/bhp
-hr
8.6
12.6
g/gal
178
262
PM
g/bhp
-hr
0.32
0.44
g/gai
6.7
9.2
Table 5 - Estimated Controlled Emission Rates for
Locomotives Manufactured in 2002-2004 (Tier 1)


Line-Haul
Switch
HC
g/bhp
-hr
0.47
1.01
g/gai
9.8
21
CO
g/bhp
-hr
1.28
1.83
g/gai
26.6
38.1
NOx
g/bhp
-hr
6.7
9.9
g/gai
139
202
PM
g/bhp
-hr
0.32
0.44
g/gai
6.7
9.2
Table 6 - Estimated Controlled Emission Rates for
Locomotives Manufactured after 2004 (Tier 2)


Line-Haul
Switch
HC
g/bhp
-hr
0.26
0.52
g/gai
5.4
11
CO
g/bhp
-hr
1.28
1.83
g/gal
26.6
38.1
NOx
g/bhp
-hr
5.0
7.3
g/gal
103
152
PM
g/bhp
-hr
0.17
0.21
g/gal
3.6
4.3

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Emission Inventory Estimation

Total emissions can be calculated by multiplying the emission factors (in g/gal)
by the fuel consumption rates (in million-gal/yr) to give annual emission rates
(in metric tons per year). This metric estimate can be converted to standard tons
(or short tons) per year, by multiplying it by 1.1.

In the United States, the great majority of fuel consumed by locomotives
each year is used in line-haul freight service.  Smaller amounts are also
used in switching and passenger service. EPA's estimates of these fuel
volumes are shown in Table 7. EPA's estimates of annual emission rates
calculated from these fuel consumption rates are shown in Table 8.
Table 7 - 1996 Locomotive Fuel Consumption
by Service Category (million gal/year)
National Freight Line-Haul
National Freight Switching
Local and Regional Freight
Passenger
3,331
270
215
133
Table 8 - Estimated 1996 Nationwide Locomotive
Emission Rates (thousand short tons per year)
HC
47
CO
119
NOx
1,202
PM
30
For More Information
For further information on emission factors for locomotives, please write
to:

       U.S. Environmental Protection Agency
       Engine Programs and Compliance Division
       2565 Plymouth Road
       Ann Arbor, MI 48105
Additional documents on locomotive emission standards are available
electronically from the EPA Internet server at:

       http ://www. epa.gov/OMSWWW/locomotv.htm

or by calling (734) 668-4333.

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Table 9 - Fleet Average Emission Factors
For All Locomotives

Year
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040

HC
0.52
0.52
0.52
0.52
0.52
0.51
0.50
0.48
0.47
0.46
0.45
0.44
0.44
0.43
0.42
0.42
0.41
0.40
0.40
0.39
0.39
0.38
0.38
0.37
0.37
0.36
0.36
0.35
0.35
0.34
0.34
0.33
0.33
0.32
0.32
0.31
0.31
0.31
0.31
0.30
0.30
0.30
(g/bhp
CO
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
1.32
-hr)
NOx
13.30
13.16
12.74
11.96
11.22
10.49
9.60
8.92
8.51
8.29
8.09
7.84
7.74
7.62
7.50
7.37
7.26
7.14
7.04
6.94
6.84
6.75
6.65
6.56
6.46
6.37
6.29
6.20
6.12
6.04
5.96
5.88
5.80
5.73
5.66
5.58
5.54
5.52
5.49
5.47
5.44
5.41

PM
0.33
0.33
0.33
0.33
0.33
0.33
0.32
0.31
0.30
0.29
0.28
0.28
0.27
0.27
0.26
0.26
0.25
0.25
0.25
0.24
0.24
0.24
0.23
0.23
0.22
0.22
0.22
0.21
0.21
0.21
0.20
0.20
0.20
0.19
0.19
0.19
0.19
0.19
0.18
0.18
0.18
0.18

HC
10.7
10.7
10.7
10.7
10.7
10.7
10.4
10.1
9.8
9.6
9.4
9.1
9.1
8.9
8.8
8.7
8.5
8.4
8.3
8.2
8.1
7.9
7.8
7.7
7.6
7.5
7.4
7.3
7.2
7.1
7.0
6.9
6.8
6.7
6.6
6.5
6.4
6.4
6.3
6.3
6.2
6.2

CO
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
27.4
(g/gai)
NOx
276.7
273.8
265.0
248.8
233.3
218.1
199.8
185.6
177.0
172.5
168.3
163.0
161.1
158.5
155.9
153.4
151.0
148.5
146.5
144.4
142.4
140.3
138.3
136.4
134.4
132.5
130.7
129.0
127.2
125.6
124.0
122.3
120.7
119.2
117.6
116.1
115.3
114.9
114.3
113.7
113.2
112.6

PM
6.8
6.8
6.8
6.8
6.8
6.8
6.6
6.4
6.2
6.0
5.9
5.7
5.7
5.6
5.5
5.4
5.3
5.2
5.1
5.1
5.0
4.9
4.8
4.7
4.7
4.6
4.5
4.4
4.4
4.3
4.2
4.2
4.1
4.0
4.0
3.9
3.9
3.9
3.8
3.8
3.7
3.7

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