Methodology for Estimating Emission
Reductions and Cost Savings from
Missoula Railyard Idle Reduction Policy
and Auxiliary Power Unit Installation
United States
Environmental Protection
tl Agency
-------
Methodology for Estimating Emission
Reductions and Cost Savings from
Missoula Railyard Idle Reduction Policy
and Auxiliary Power Unit Installation
Air Program
U.S. EPA Region 8
and
Transportation and Climate Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
oEPA
United States EPA-420-F-19-010
Environmental Protection
Agency February 2019
-------
Table of Contents
Project Overview 2
Grantee Reported Switcher Locomotive Emissions 2
Idle Hour Estimates Adjusted for Yard Idling Policy 4
Estimated APU Project Costs and Emission Benefits 7
Estimated APU Project Fuel Cost Savings 7
Acronyms & Abbreviations 11
Page 1 of 11
-------
Project Overview
An overview of information in this document was published on EPAs Ports Initiative website. The Ports Initiative
website includes information on other promising practices for ports, railyards, and surrounding communities.
The railyard project focuses on reducing air pollution and saving money from reduced fuel consumption by
switcher locomotives at the Montana Rail Link (MRL) Railyard in Missoula, Montana during colder months. Fuel
savings were realized by installing auxiliary power units (APUs) on eight switcher locomotives, and changing the
mandatory idling policy to better fit daily temperature conditions.
The city of Missoula, Montana is located along the Clark Fork River in western Montana and is the second largest
metropolitan area in the state. Missoula has average low temperatures below 40 degrees Fahrenheit for eight
months out of the year.
The APU installation portion of this project was partially funded by a 2009 Diesel Emissions Reduction Act (DERA)
grant (DE - 97897201) awarded to the Missoula Metropolitan Planning Organization that exercises jurisdictional
authority over local air quality issues. The grant help fund installation of APUs in eight resident switcher
locomotives at a mid-sized railyard, located adjacent to downtown Missoula, Montana operated by MRL, a Class II
regional railroad.
Grantee Reported Switcher Locomotive Emissions
Switcher locomotive roster and engine characteristics were provided by the grantee. The grantee reports 8 of the
16 switcher locomotives presented in Table 1 as being assigned to the Missoula, MT switchyard.
Table 1
Switcher Engine Grant Roster and Engine Characteristics
Engine No.
Make
Model
Engine Year
HP
Tier
Idle Fuel Use (gal/hr
Prolonged Idling (hr/yr
1
EMDSW
12 Cyl-567C
1957
1200
Un
3.5
2618
2
EMDSW
12 Cyl-567C
1957
1200
Un
3.5
2618
3
EMDSW
12 Cyl-645E
1968
1500
Un
3.5
2618
4
EMDSW
12 Cyl-645E
1968
1500
Un
3.5
2618
5
EMD GP9
16 Cyl-567C
1957
1700
Un
3.5
2618
6
EMD GP9
16 Cyl-567C
1951
1750
Un
3.5
2618
7
EMD GP9
16 Cyl-567C
1957
1750
Un
3.5
2618
8
EMD GP9
16 Cyl-567C
1956
1750
Un
3.5
2618
9
EMD GP9
16 Cyl-567C
1957
1500
Un
3.5
2618
10
EMD GP9
16 Cyl-567C
1957
1750
Un
3.5
2618
11
EMD GP3^
16 Cyl-567D3/
1964
2500
Un
5
2618
12
EMD GP3^
16 Cyl-567D3/
1964
2500
Un
5
2618
13
EMD GP3^
16 Cyl-567D3/
1965
2500
Un
5
2618
14
EMD GP3^
16 Cyl-567D3/
1965
2500
Un
5
2618
15
EMD GP3^
16 Cyl-567D3/
1965
2500
Un
5
2618
16
EMD GP3^
16 Cyl-567D3/
1979
2500
0+
5
2618
Page 2 of 11
-------
Emissions were calculated using EPA-approved switcher locomotive emissions factors in grams per brake
horsepower hour (g/bhp-hr) with an EPA-provided switcher fuel consumption conversion factor of 15.2 brake
horsepower hour per gallon (bhp-hr/gal)1 (Tables 2 and 3; Eq. 1).
Table 2
SwitcherEmission Factors (g/bhp-hr)
PM10
HC
NOx
CO
VOCs
PM2.5
Uncontrolled
0.44
1.01
17.40
1.83
1.06
0.43
TierO
0.44
1.01
12.60
1.83
1.06
0.43
Tier0+
0.23
0.57
10.60
1.83
0.60
0.22
Tier 1
0.43
1.01
9.90
1.83
1.06
0.42
Tier 1+
0.23
0.57
9.90
1.83
0.60
0.22
Tier 2
0.19
0.51
7.30
1.83
0.54
0.18
Tier 2+
0.11
0.26
7.30
1.83
0.27
0.11
Tier 3
0.08
0.26
4.50
1.83
0.27
0.08
Tier 4
0.015
0.08
1.00
1.83
0.08
0.01
"+" Indicates these are revised standards in 40 CFR 1033
All but one of the switcher engines in the grant were originally manufactured before 1973, the start date for Tier 0
requirements. Therefore, although the grantee reported Tier 0 engines, emissions reductions for 15 engines have
been calculated based on the factors for "uncontrolled engines (un)".
A locomotive operator trade association reported fuel consumption of 5 gallons per hour (gph) for EMD GP35
locomotives and 3.5 gph for all other EMD switcher locomotives on the fleet roster.2 The total grant reported
idling hours is 2618.
/15.2 bhp hr\ /0.44 gpM10,uncontrolled} f 3.5 gal \ /2618 hr idling\ /l.10231X10~6 ton\
^ ' v gal ) v bhp hr ) \engine-hr) v yr ) v 1 g )
= 0.068 tonsPMi0 engine-1 yr-1
Table 3 provides a summary of the emissions as a result of idling from the 16 switchers in the roster calculated
using Equation 1 and the emission factors for each pollutant.
1 Office of Transportation and Air Quality, U.S. Environmental Protection Agency, "Emission Factors for Locomotives,"
Technical Highlights, EPA-420-F-09-025, April 2009.
2 Source: International Association of Railway Operating Officers
Page 3 of 11
-------
Table 3
Switcher Roster Emissions From Idling
Annua
Emissions (tons/engine-yr)
Engine No.
PM10
HC
NOx
CO
VOCs
PM2.5
1
0.068
0.155
2.671
0.281
0.163
0.066
2
0.068
0.155
2.671
0.281
0.163
0.066
3
0.068
0.155
2.671
0.281
0.163
0.066
4
0.068
0.155
2.671
0.281
0.163
0.066
5
0.068
0.155
2.671
0.281
0.163
0.066
6
0.068
0.155
2.671
0.281
0.163
0.066
7
0.068
0.155
2.671
0.281
0.163
0.066
8
0.068
0.155
2.671
0.281
0.163
0.066
9
0.068
0.155
2.671
0.281
0.163
0.066
10
0.068
0.155
2.671
0.281
0.163
0.066
11
0.097
0.222
3.816
0.401
0.233
0.094
12
0.097
0.222
3.816
0.401
0.233
0.094
13
0.097
0.222
3.816
0.401
0.233
0.094
14
0.097
0.222
3.816
0.401
0.233
0.094
15
0.097
0.222
3.816
0.401
0.233
0.094
16
0.050
0.125
2.325
0.401
0.132
0.049
Total preventable switcher idling emissions were calculated for the 16 switcher locomotives included in the
grantee's reporting (Table 4).
Table 4
Total Switcher Preventable Engine Emissions
PM10
HC
NOx
CO
VOCs
PM2.5
TOTAL (tons/yr)
1.208
2.783
48.120
5.218
2.931
1.172
Idle Hour Estimates Adjusted for Yard Idling Policy
The updated railyard policy calls for long-term idling of switcher engines or APU usage only during temperatures
below 40 degrees Fahrenheit. This policy facilitates quick engine start-up and prevents engine damage during
near-freezing conditions.
Missoula's northern continental climate requires 24-hour engine activity for much of the year. National Oceanic
and Atmospheric Administration (NOAA) data3 can be used to determine the average number of hours which fall
3 National Oceanic and Atmospheric Administration, "Local Climatological Data for Missoula International Airport, MT US,"
accessed May 1, 2018, https://www.ncdc.noaa.gOv/cdo-web/datasets/LCD/stations/WBAN:24153/detail.
Page 4 of 11
-------
below the 40-degree threshold per year. For the years 2010 - 2017, the annual average of hours below 40-
degress was 3,557 (Table 5).
Table 5
Annual "Must Idle" Condition (<40degrees Fahrenheit) Hours
Year
2010
2011
2012
2013
2014
2015
2016
2017
"Must Idle" Hours Count
3623
3746
3511
3752
3527
3376
3214
3709
Average Annual "Must Idle" Hours
3557
To clarify, not all 3557 hours are idling hours, as most of them could fall within normal winter usage hours. To
estimate the number of "must-idle" hours, or time when locomotives are expected to idle solely due to the
ambient temperature and engine maintenance, the reported annual activity hours per engine (5,736) is converted
to represent the average daily activity hours- equaling 15.7. This is rounded to the nearest whole number (16) and
assumed to represent a typical work day. Without detailed yard logs, it's assumed that the 16 hours represents
two shifts from early morning to late afternoon (04:00 - 20:00). This would leave an eight-hour window overnight
in which locomotives, due to yard inactivity, would be required to idle continuously during sub 40-degree
Fahrenheit conditions. Using the hourly Missoula meteorological data from NOAA for the eight-year period
(filtered for only the hours 20:00 - 04:00) an average annual "off-shift must-idle" hours number is calculated at
1,355. This number represents the bulk of the idling hours reduced by APU usage after APU install (Table 6).
Table 6
Annual Overnight (20:00—4:00) "Must Idle" Condition (<40 degrees Fahrenheit) Hours
Year
2010
2011
2012
2013
2014
2015
2016
2017
Overnight "Must Idle" Hours Count
1417
1404
1318
1420
1323
1281
1262
1412
Avg. Annual Overnight "Must Idle" Hours
1355
A smaller annual idling-hours number will be added to this bulk-hours total. This smaller number comes from a
calculation derived from the reported annual use-hours, annual idling-hours and "summer hours," which together
is assumed to represent a complete picture of daily use throughout the year. This smaller number of idling hours
accounts for the grantee's estimates of locomotive movements during work shifts, annual idling hours and
summer non-idle hours derived from a strictly defined 275/90-day winter/summer year. Using these reported
hours, a daily average prolonged idling period of 1.15 hours per day (418 hours annually from Equation 2) is
assumed during normal usage hours.
Ea 2* (2612 hridllna\ — (27Z daywinter * g hroff-shift\ _ j^g hrldllna,on-shift
v yr J \ yr day J yr
Average annual total hours predicted after yard policy change and APU install: 1,773 (1,355 + 418)
Average annual total idling hours replaced by APU usage and ambient temperature yard policy: 2618 (grant
reported)
Based on the above, engine activity would be reduced by 845 hours annually due to the yard policy change (2618
hours minus 1773 hours = 845 hours)
Aggregate APU emissions for the 8 Missoula railyard HotStart DDHSJR-110 APUs with Yanmar 2TNV70-ASA 2008
EPA Tier 4 engines were based on the APU engine characteristics (Table 7) and EPA emission factors for non-road
Page 5 of 11
-------
compression ignition engines4 (Table 8). Aggregate APU emissions were for temperature-defined "must-idle"
hours tabulated as Local Climatological Data (LCD) hours below 40 degrees Fahrenheit as measured at Missoula
International Airport, WBAN station ID: 24153. Accessed from NOAA, National Centers for Environmental
Information's (NCEI) LCD clearinghouse (www.ncdc.noaa.gov/cdo-web/datatools/lcd). APU usage hours were
restricted to those hours reported as prolonged idling hours by the grantee (Table 9).
Table 7
APU Engine Characteristics
Engine Make
Model
Power kW
Tier
Number
Yanmar
2TNV70-ASA
10.2
4
16
Table 8
Tier 4 Emission Standards 8
-------
Estimated APU Project Costs and Emission Benefits
APU technology and install costs for the 16 switchers were reported by the grantee (Table 11).
Table 11
APU Install Costs (USD)
Locomotive No.
Tech Unit Cost
Install Cost
1
27366.93
2566.16
2
27151.17
3591.69
3
27755.24
3623.84
4
27596.37
4119.79
5
27566.70
3903.97
6
27994.90
3293.22
7
27413.28
2995.13
8
27794.54
3143.81
9
27808.78
3584.41
10
27926.00
3429.45
11
27036.88
2139.07
12
27037.20
2087.74
13
27563.35
3018.58
14
27157.77
2635.90
15
27464.82
2200.77
16
27556.94
1461.00
TOTAL(USD)
440190.87
47794.53
Total cost of APU installs on 16 locomotives was $487,985. The average cost per locomotive retrofit was applied
to the eight Missoula yard switchers and used to find cost over a 10-year APU lifecycle per unit reduction of
pollutant for oxides of nitrogen, particulate matter and carbon monoxide (Table 12).
Table 12
Lifecycle Cost per Unit Reduction
NOx
PM
CO
10-year cost (USD/ton)
1064.37
45146.41
15677.6£
10-year cost (USD/lb)
0.53
22.57
7.84
Estimated APU Pirojet II Cost Savings
Reduced fuel consumption cost savings were tabulated monthly and summed to find approximate year end cost
savings. First, temperature dependent APU operation hours were further broken into monthly counts over the 8-
year study period (Table 13).
Page 7 of 11
-------
Table 13
Count of "Off-Shift" Hours Below 40 Between Jan, 2010--Dec, 2017
2010
2011
2012
2013
2014
2015
2016
2017
Jan
242
229
236
242
243
247
247
248
Feb
214
209
231
223
223
195
210
210
Mar
211
214
188
199
213
138
199
138
Apr
142
162
79
123
133
134
66
116
May
61
38
47
23
26
25
7
45
Jun
0
2
5
3
0
0
6
4
Jul
0
0
0
0
0
0
0
0
Aug
0
0
0
0
0
0
0
0
Sep
1
5
2
8
10
15
9
23
Oct
102
92
119
158
46
80
67
161
Nov
202
212
172
203
186
219
205
222
Dec
242
241
239
238
244
228
246
244
Yanmar engine specifications list APU fuel consumption rates as either 0.35 grams per hour (gph) (low setting) or
0.76 gph (high setting). Fuel consumption was calculated for temperature specified operation hours. The high fuel
consumption rate was used to give a conservative estimate of fuel savings after APU retrofits. Fuel costs over the
study period were averaged for No. 2 Ultra Low-Sulfur Diesel (ULSD). Averaged monthly fuel prices were
calculated from weekly ULSD retail prices provided by the U.S. Energy Information Administration at:
https://www.eia.gov/opendata/qb.php?sdid=PET.EMD EPD2DXL0 PTE NUS DFG.W (Tables 14 and 15).
Table 14
Monthly APU Fuel Costs (USD) at High Consumption Rate (0.76 gph)
2010
2011
2012
2013
2014
2015
2016
2017
Jan
526.43
592.57
690.76
722.27
722.41
565.26
404.11
488.5C
Feb
456.08
572.41
697.36
700.24
678.61
426.02
320.66
412.1C
Mar
470.42
638.44
593.20
618.76
651.11
306.37
317.92
270.04
Apr
333.18
503.94
250.66
370.81
404.17
285.78
109.80
229.93
May
145.13
120.41
145.59
71.03
81.35
57.39
14.34
89.8C
Jun
2.58
9.42
17.57
12.14
3.41
2.51
13.16
9.83
Jul
2.54
3.41
3.25
3.38
3.39
2.44
2.10
2.18
Aug
2.59
3.37
3.48
3.41
3.35
2.27
2.05
2.27
Sep
4.81
17.94
9.86
27.54
32.14
30.75
18.47
51.11
Oct
239.22
268.85
373.82
469.88
131.89
155.37
127.12
344.34
Nov
484.80
641.82
526.38
595.60
518.76
412.76
382.05
493.31
Dec
599.19
710.56
722.90
705.53
635.44
402.21
471.46
541.99
Page 8 of 11
-------
Table 15
Monthly APU Fuel Costs (USD) at Low Consumption Rate (0.35 gph)
2010
2011
2012
2013
2014
2015
2016
2017
Jan
242.44
272.90
318.12
332.62
332.69
260.32
186.10
224.97
Feb
210.04
263.61
321.15
322.48
312.52
196.19
147.67
189.78
Mar
216.64
294.02
273.18
284.96
299.85
141.09
146.41
124.36
Apr
153.44
232.08
115.44
170.77
186.13
131.61
50.57
105.89
May
66.84
55.45
67.05
32.71
37.47
26.43
6.60
41.36
Jun
1.19
4.34
8.09
5.59
1.57
1.16
6.06
4.53
Jul
1.17
1.57
1.50
1.56
1.56
1.12
0.97
1.00
Aug
1.19
1.55
1.60
1.57
1.54
1.04
0.95
1.04
Sep
2.22
8.26
4.54
12.68
14.80
14.16
8.51
23.54
Oct
110.17
123.81
172.15
216.39
60.74
71.55
58.54
158.58
Nov
223.26
295.58
242.41
274.29
238.90
190.09
175.94
227.18
Dec
275.94
327.23
332.92
324.92
292.64
185.23
217.12
249.60
Locomotive main engine monthly fuel costs due to prolonged idling were based upon the same pricing data,
reported prolonged idling from the grantee and fuel consumption at idle rates from the International Association
of Railway Operating Officers. Consumption rate for EMD SW1200, SW1500 and GP9 locomotives was fixed at 3.5
gph. Fuel consumption rate for EMD GP35 locomotives was set at 5 gph (Tables 16 and 17).
Table 16
Monthly Locomotive Fuel Costs (USD/engine) - GP35; 5 gph at idle
2010
2011
2012
2013
2014
2015
2016
2017
Jan
4040.24
4804.75
5435.58
5543.23
5521.60
4250.85
3038.96
3658.8C
Feb
3573.03
4591.10
5063.15
5265.55
5102.86
3660.78
2559.69
3289.61
Mar
4137.89
5537.56
5852.41
5769.09
5673.85
4108.67
2964.14
3621.5C
Apr
4203.28
5578.18
5647.84
5393.93
5440.93
3818.64
2952.93
3544.4£
May
4357.71
5739.37
5642.51
5488.98
5591.81
4095.20
3282.68
3631.29
Jun
508.79
678.44
648.34
664.00
673.82
495.59
417.88
433.06
Jul
519.02
696.11
663.27
689.11
692.23
496.92
428.60
444.98
Aug
527.37
688.01
709.88
695.98
684.12
462.56
418.99
462.56
Sep
4043.73
5266.63
5654.70
5436.20
5205.07
3438.11
3286.11
3822.07
Oct
4327.79
5385.95
5806.03
5509.55
5219.87
3572.93
3480.95
3962.87
Nov
4309.65
5437.85
5490.00
5268.68
5005.85
3385.96
3346.84
3992.26
Dec
4598.68
5475.86
5617.40
5505.36
4837.08
3275.45
3559.81
4125.69
Page 9 of 11
-------
Table 17
Monthly Locomotive Fuel Costs (USD/engine) - GP9, SW; 3.5 gph at idle
2010
2011
2012
2013
2014
2015
2016
2017
Jan
2828.17
3363.32
3804.91
3880.26
3865.12
2975.59
2127.27
2561.16
Feb
2501.12
3213.77
3544.21
3685.89
3572.00
2562.54
1791.79
2302.73
Mar
2896.52
3876.29
4096.69
4038.36
3971.70
2876.07
2074.90
2535.05
Apr
2942.30
3904.73
3953.49
3775.75
3808.65
2673.05
2067.05
2481.14
May
3050.40
4017.56
3949.76
3842.29
3914.26
2866.64
2297.88
2541.90
Jun
356.15
474.91
453.84
464.80
471.67
346.91
292.52
303.14
Jul
363.31
487.28
464.29
482.38
484.56
347.84
300.02
311.49
Aug
369.16
481.61
496.92
487.18
478.89
323.79
293.30
323.79
Sep
2830.61
3686.64
3958.29
3805.34
3643.55
2406.68
2300.28
2675.45
Oct
3029.45
3770.16
4064.22
3856.68
3653.91
2501.05
2436.67
2774.01
Nov
3016.76
3806.49
3843.00
3688.08
3504.10
2370.17
2342.79
2794.58
Dec
3219.07
3833.10
3932.18
3853.75
3385.96
2292.81
2491.87
2887.98
Fuel cost savings for the Montana Rail Link (MRL) switcher engines were based upon the average fuel savings of
the 16 retrofitted switcher engines in the Missoula Metropolitan Planning Organization (MPO) DERA grant. Year-
end fuel savings were adjusted to 2010 USD to compare total savings over the APU life cycle to the initial
investment cost for the APU materials and installation labor (Table 18).
Table 18
8-year Fuel Cost Savings for the 8-locomotive Missoula Switcher Fleet (2010 USD)
2010
2011
2012
2013
2014
2015
2016
2018
228321
282808
292942
280438
271857
191241
159256
18084;
TOTAL:
$1,887,707.92
Note: detailed activity logs of each switcher locomotive, railyard assignment logs, activity data, and engine
characteristics of the estimated 30 line-haul locomotives that pass through the Missoula yard daily would be
useful in further ensuring emission benefits and cost savings estimates are accurate.
Page 10 of 11
-------
Acronyms & Abbreviations
APU - Auxiliary Power Unit
bhp-hr/gal - brake horsepower hour per gallon
CFR - Code of Federal Regulations
CO - Carbon Monoxide
DERA- Diesel Emissions Reduction Act
EPA - U.S. Environmental Protection Agency
g/bhp-hr - grams per brake horsepower hour
GPH - Gallons Per Hour
HC- Hydrocarbons
HP - Horsepower
kW - Kilowatt
NMHC- Non-methane Hydrocarbon
MPO - Metropolitan Planning Organization
MRL- Montana Rail Link
NOAA - National Oceanic and Atmospheric Administration
NOx - Nitrogen oxides
PM 10 — Particulate Matter smaller than 10 micrometers in diameter
PM2.5- Particulate Matter smaller than 2.5 micrometers in diameter
ULSD - Ultra Low-Sulfur Diesel
Un - Uncontrolled Engines
USD - United States Dollars
VOC - Volatile Organic Compounds
Page 11 of 11
------- |