EMD MP15 Switcher Locomotives

Last revised: March 10, 2023

By: Adam Burns

The MP15 series was Electro-Motive's immediate follow-up to the earlier SW1500 line, manufactured between 1966 - 1974. This was the first switcher EMD offered as essentially a potential road-switcher with its 1,500 horsepower and operational Blomberg trucks.

This continued with the MP15 where Blombergs became standard and was even equipped with larger fuel tank for main line freight service.  EMD also lengthened the frame and the model also featured the same electrical components as the builder's "Dash 2" line of road-switchers.

When EMD released alternating current technology in 1975; this changed the designation of the original model to MP15DC and the new variant as the MP15AC. 

In addition, the MP15T was later offered in 1984 sporting a turbocharged eight-cylinder prime mover for improved fuel economy. Overall, the series sold relatively well and many MP15's remain in service on both large and small railroads.

Photos

A recently delivered Missouri Pacific MP15DC, #1536, in the fall of 1974. American-Rails.com collection.

History and Background

Throughout the history of Electro-Motive's switcher line the builder saw successful sales, more than could be said for its road-switchers after the 1980s.  

From the earliest SC and NW models to the final series presented here, the manufacturer produced thousands of switchers, many of which remain on Class I rosters for light-duty service.  

The MP15 (later redesignated as the MP15DC) was the first in the series and interestingly, was meant to not only for yard, industrial, and light branch duties but also as a general road switcher. It replaced the earlier SW1500, featuring a larger fuel tank (1,400 gallons) and Blomberg trucks as standard for general road service.

Interestingly, EMD actually considered the MP15 a true road-switcher rather than a switcher. While it carried the look of the latter, internally it was indeed a small road switcher, essentially a GP7.

With the introduction of the MP15AC in August, 1975, EMD made a number of updates to the locomotive.  As Bob Hayden notes in his book, "Diesel Locomotives: Cyclopedia, Volume 2," it was 18 inches longer than the MP15DC which allowed for a larger fuel tank (1,600 gallons). 

In addition, EMD moved the radiator air-intakes to the lower side of the hood on the locomotive's pilot end.  As Louis Marre points out in his book, "The Contemporary Diesel Spotters Guide: A Comprehensive Reference Manual To Locomotives Since 1972," this design was actually based from EMD's successful SD40T-2 and SD45T-2, the so-called "Tunnel Motors."

These powerful road-switchers were almost entirely purchased by Southern Pacific (along with the Rio Grande) and featured air intakes low on the frame to grab fresh air as through the many tunnels and snowsheds on Donner Pass.

Marre goes on to note the MP15 series was marketed to railroads as a combination switcher/light road-switcher to replace aging GP7s and GP9s.  Interestingly, its lack of a toilet ultimately hindered sales as some state laws required this feature on locomotives used as either lead units or in MU sets outside of yard work. 

In addition, the MP15AC was more expensive than its earlier counterpart (MP15DC), further hurting sales.  Nevertheless, it did sell relatively well. The MP15AC accomplished its use of "AC" power by using an alternator, which then converted the power back to DC, through the use of a silicon rectifier.

Data Sheet and Specifications

Entered Production2/1974 (Missouri Pacific #1530)
Years Produced (MP15DC)2/1974 - 1/1983
Years Produced (MP15AC)8/1975 - 12/1983
Years Produced (MP15T)10/1984 - 5/1987
EMD ClassMP15DC, MP15AC, MP15T
Engine (MP15DC, MP15AC)645E (12 Cylinder)
Engine (MP15T)645E (8 Cylinder, Turbocharged)
Engine BuilderEMD/GM
Horsepower1500
RPM800
Length (MP15DC)47' 8"
Length (MP15AC)49' 2"
Length (MP15T)50' 2"
Height (Top Of Rail To Top Of Cab)15' 0"
Width10' 3"
Weight250,000 Lbs
Fuel Capacity (MP15DC)1400 Gallons
Fuel Capacity (MP15AC, MP15T)1600 Gallons
Air CompressorWXO (Gardner-Denver)
Air Brake Schedule24L (Westinghouse)
TrucksB-B
Truck TypeBlomberg
Truck Wheelbase9' 0"
Wheel Size40"
Traction Motors (MP15DC)D77 (4), EMD/GM
Traction Motors (MP15AC, MP15T)D79AR10 (4), EMD/GM
Traction Generator (MP15DC)D15C, EMD/GM
Traction Alternator (MP15AC, MP15T)D14, EMD/GM
Auxiliary GeneratorEMD/GM
MU (Multiple-Unit)Optional
Dynamic BrakesNo
Gear Ratio62:15
Tractive Effort/Starting62,000 Lbs
Tractive Effort/Continuous48,800 Lbs at 9.3 mph
Top Speed65 mph

Production Rosters

MP15DC

Total Built = 339

Owner Road Number Order Number/Serial Number Completion Date
Southern Pacific 2690-2696 73625-1 thru 73625-7 12/1974
Union Railroad 10-14 73645-1 thru 73645-5 7/1974
Missouri Pacific 1530-1534 73749-1 thru 73749-5 2/1974
Missouri Pacific 1535-1539 73678-1 thru 73678-5 9/1974
Missouri Pacific 1540-1544 73778-1 thru 73778-5 9/1974
Pittsburgh & Lake Erie 1574-1583 73694-1 thru 73694-10 6/1974 - 7/1974
Cities Service Corporation 109 74618-1 7/1974
Rockdale, Sandow & Southern 13-15 74620-1 thru 74620-3 11/1974
Bauxite & Northern 15-16 74621-1 and 74621-2 11/1974
Point Comfort & Northern 11-13 74622-1 thru 74622-3 11/1974
Reading 2771-2780 74641-1 thru 74641-10 12/1974
St Marys Railroad 504 74645-1 10/1974
Chicago & North Western 1307-1316 74662-1 thru 74662-10 3/1975
Chicago & North Western 1302-1306 74762-1 thru 74762-5 2/1975
Union Railroad 15-21 74667-1 thru 74667-7 6/1975 - 7/1975
Pittsburgh & Lake Erie 1584-1598 74668-1 thru 74668-15 5/1975
Louisville & Nashville 5030-5039 74778-1 thru 74778-10 1/1975
Belt Railway of Chicago 533-534 74683-1 and 74683-2 6/1975
Missouri Pacific 1545-1554 74791-1 thru 74791-10 2/1975
Kansas City Southern 4363-4366 74692-1 thru 74692-4 8/1975
St Louis-San Francisco Railway (Frisco) 361-365 74694-1 thru 74694-5 3/1975
Southern Pacific 2697-2701 74697-1 thru 74697-5 1/1975 - 2/1975
Manufacturers Railway (St. Louis) 251-252 75611-1 and 75611-2 8/1975
W.R. Grace & Company 121-122 75612-1 and 75612-2 8/1975
North Louisiana & Gulf 42-45 75619-1 thru 75619-4 11/1975
Cambria & Indiana Railroad 19-20 75627-1 and 75627-2 8/1975
Tennessee Eastman 2 756060-1 11/1975
Union Railroad 22-24 756070-1 thru 756070-3 3/1976
Texas & Northern 998-999 756085-1 and 756085-2 12/1975
U.S. Steel-Fairfield Works 170 756100-1 5/1976
U.S. Steel-Minntac Works 955-965 756119-1 thru 756119-11 5/1976
Brewster Phosphates 18 756127-1 1/1976
Lake Erie, Franklin & Clarion 25 756146-1 8/1976
Arizona Public Service 2 756149-1 6/1977
Terminal Railway-Alabama State Docks 761 756150-1 8/1976
St. Marys Railroad 505 756156-1 6/1976
Swift & Company 1976 756158-1 12/1976
U.S. Steel-Minntac Works 966-968 766000-1 thru 760000-3 8/1976
Kelly's Creek & Northwestern 1 766006-1 12/1976
Union Railroad 25-26 766013-1 and 766013-2 12/1976
Birmingham Southern 260-261 766014-1 and 766014-2 8/1976
Southern 2348-2373 767051-1 thru 767051-26 6/1977 - 7/1977
Union Railroad 27-33 766057-1 thru 766057-7 2/1977
Terminal Railway-Alabama State Docks 771-772 776002-1 and 776002-2 10/1977
Lake Erie, Franklin & Clarion 26 776021-1 10/1977
Lake Erie, Franklin & Clarion 27 786122-1 12/1978
Georgetown Railroad 1011 786144-1 12/1978
Southern 2374-2383 787185-1 thru 787185-10 9/1979- 10/1979
Lake Erie, Franklin & Clarion 28 786234-1 11/1979
Gulf Oil Company 101 786235-1 9/1979
Houston Belt & Terminal 60-64 786236-1 thru 786236-5 10/1979
Southern 2384-2393 787244-1 thru 787244-10 11/1979
Alcoa Terminal 7 786247-1 2/1980
Terminal Railway-Alabama State Docks 801-802 796300-1 and 796300-2 10/1980
Belt Railway of Chicago 535-536 796302-1 and 796302-2 2/1980
Genesee & Wyoming 45-46 796350-1 and 796350-2 10/1980 - 11/1980
Kelly's Creek & Northwestern 2 796358-1 10/1980
Brewster Phosphates 19 796371-1 11/1980
Alton & Southern 1522 796374-1 11/1980
W.R. Grace & Company 131-132 796376-1 and 796376-2 10/1980 - 11/1980
Graysonia, Nashville & Ashdown 80 796377-1 10/1980
Point Comfort & Northern 14-15 796384-1 and 796384-2 11/1980
Georgetown Railroad 1012 806028-1 11/1980
Southern 2404-2435 817015-1 thru 817015-32 4/1982 - 5/1982
Missouri Pacific 1356-1375 817019-1 thru 817019-20 1/1982
Metro Sanitary District of Greater Chicago 4 816030-1 1/1983
Terminal Railway-Alabama State Docks 821-822 816033-1 and 816033-2 6/1982
Southern 2394-2403 817037-1 and 817037-10 5/1982 - 6/1982
Missouri Pacific 1376-1392 827018-1 thru 827018-17 11/1982 - 12/1982
Manufacturers Railway 254 826025-1 1/1983
Texas City Terminal 35-37 827028-1 thru 827028-3 11/1982

MP15AC

Total Built = 217

Owner Road Number Order Number/Serial Number Completion Date
Milwaukee Road 466-497 75625-1 thru 75625-32 10/1975 - 11/1975
Milwaukee Road 434-465 75629-1 thru 75629-32 1/1976 - 2/1976
Southern Pacific 2732-2735 756053-1 thru 756053-4 10/1975
Southern Pacific 2702-2731, 2736-2759 756064-1 thru 756064-54 8/1975 - 9/1975
Electro-Motive (Demonstrator) 115 (became Georgetown Railroad 1013) 757129-1 10/1975
Kennecott Copper Corporation 906 756152-1 12/1976
Long Island Rail Road 150-172 766043-1 thru 766043-23 3/1977 - 4/1977
Seaboard Coast Line 4000-4019 777024-1 thru 777024-20 10/1977
Seaboard Coast Line 4200-4224 777032-1 thru 777032-25 2/1978
Louisville & Nashville 4225-4234 777038-1 thru 777038-10 3/1978
Kennecott Copper Corporation 701,704 776117-1 and 776117-2 12/1978
Kennecott Copper Corporation 120-122 776128-1 thru 776128-3 12/1978
Electro-Motive (Demonstrator) 116 787150-1 7/1978
Weyerhaeuser (Golden Triangle) G1 796389-1 10/1980
Terminal Railway-Alabama State Docks 803 806003-1 10/1980
Missouri-Kansas-Texas (Katy) 56-59 806026-1 thru 806026-4 10/1980
Eastman Kodak 10 806035-1 4/1981
Rockwell-Hanford 3728 816059-1 9/1982
Rockwell-Hanford 3727 836053-1 12/1983

MP15T

Total Built = 43

Owner Road Number Order Number/Serial Number Completion Date
Seaboard System 1200-1214 837079-1 thru 837079-15 10/1984 - 11/1984
Seaboard System 1215-1222 847037-1 thru 847037-8 3/1985
Seaboard System 1223-1241 857074-1 thru 857074-19 11/1985 - 12/1985
Dow Chemical 957 866139-1 5/1987

Export Production Roster

MP15DC

Total Built = 12

Owner Road Number Serial Number Order Number Completion Date
BC Hydro & Power Authority 151-153 75626-1 thru 75626-3 C377 (General Motors Diesel) 11/1975
Altos Hornos de México (Mexico) 146-148 756093-1 thru 756093-3 - 01/76
Quebec Iron & Titanium (Romaine River Railway) 9 768030-1 C402 (General Motors Diesel) 3/1977
Mexico Minerals (Mexico) No Number 788018-1 - 10/1979
Altos Hornos de México (Mexico) 159 788061-1 - 12/1978
Quebec Iron & Titanium (Romaine River Railway) 10 808008-1 C433 (General Motors Diesel) 10/1980
Altos Hornos de México (Mexico) 166 808010-1 11/80 - 11/80
Mexico Minerals (Mexico) No Number 808050-1 - 1/1982

MP15AC

Total Built = 25

Owner Road Number Serial Number Completion Date
Ferrocarril Nacional de México 9801-9825 818040-1 thru 818040-25 6/1983 - 7/1983

The MP15T was essentially a variant of the MP15AC in that it featured a turbocharged prime mover, which was meant to be more fuel efficient (it was also slightly longer than the MP15AC at 50' 2") using only an eight-cylinder version of EMD's 645E prime mover. 

The model was built between October, 1984 and November, 1987. Few MP15Ts were ever built, as all but one were manufactured for the Seaboard System, which purchased 42 units.

Sources

  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • Hayden, Bob. Diesel Locomotives: Cyclopedia, Volume 2 (Model Railroader). Milwaukee: Kalmbach Publishing Company, 1980.
  • McDonnell, Greg. Locomotives: The Modern Diesel & Electric Reference, 2nd Edition. Buffalo: Boston Mills Press/Firefly Books, 2015.
  • Marre, Louis A. and Pinkepank, Jerry A. Contemporary Diesel Spotter's Guide, The: A Comprehensive Reference Manual To Locomotives Since 1972.  Milwaukee: Kalmbach Publishing Company, 1989.
  • Solomon, Brian.  EMD Locomotives.  Minneapolis: MBI Publishing Company, 2006.
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