EMD "GP9" Locomotives

Last revised: March 11, 2023

By: Adam Burns

The GP9 series, like its sister GP7, would find enormous success and even eclipse the GP7 in terms of sales to become one of the most successful diesel locomotives ever built.

Following the tremendous sales performance of the GP7, the series affectionately became known as “Geeps,” and the GP9 simply followed in that success.

Until the release of the GP7 EMD was lagging far behind the other locomotive builders, particularly the American Locomotive Company (Alco) and its early RS models. 

However, the model instantly propelled EMD as the industry leader of road switchers (along with virtually every other model type) and it only reaffirmed its dominance with the GP9.

In just five years of production the model amazingly sold more than 3,500 examples (including B units), nearly a 32% net increase in sales! 

Together the two models, aside from the SD40 series, are likely the best selling of all time, combining for over 6,000 units built when production ended on the GP9 in 1959.


A pair of Southern Pacific GP9's, #5684 and #5711, lead a westbound/southbound freight over the big lift bridge spanning the Carquinez Strait near Martinez, California circa 1956. Gordon Glattenberg photo. American-Rails.com collection.


Today, hundreds of GP9s remain either in operation on shortlines or in use aboard a tourist railroad. Others remain preserved at various museums and historical societies.  

The EMD GP9 began production in January, 1954 about five months before the GP7 was no longer offered in the builder's catalog.

The GP9 looked almost identical to its predecessor but there were some key difference in the two.

For EMD, the success of the GP7 had to surprise the company to some extent considering its lack of competing road switcher model at such a late date and more than eight years since the American Locomotive first released its RS1 model in 1941, just before the outbreak of World War I.

In a sense, EMD was poised to be successful in the road switcher market, even despite the failed BL2 design of 1948.

Western Pacific GP9 #708, F7A #921, and a GP40 appear to be tied down with their train at Milpitas, California, circa 1979. Mike Bledsoe photo. American-Rails.com collection.


Its locomotives were reliable, easy to maintain, and efficient. Once again, it was EMD's chief engineer Richard "Dick" Dilworth who laid out the general design of the GP7, and the company's styling department headed by John Markestein put the finishing touches on the new model.

As for the GP9 it carried the standard carbody appearance of the former but offered new features. First was the latest version of the company's prime mover, the 567C.

This engine offered a slight increase in horsepower of 1,750 (250 more than the GP7).

It also offered a new traction motor, the model D37 although tractive effort ratings remained the same; 65,000 pounds starting and 40,000 pounds continuous. The GP9 also weighed slightly less at just 120 tons while increasing its length to just over 56 feet..

Rio Grande GP9 #5913 lays over with other power next to the roundhouse in Pueblo, Colorado during the 1970s. American-Rails.com collection.

Those differences aside the GP9 looked very similar to the GP7. Through 1959 the model sold an astonishing 3,449 units, which is even more surprising when one realizes that the GP7 sold 2,600+ itself!

While the GP7 is credited with completing main line dieselization perhaps the GP9 is best credited with finishing off the remaining steam in America (an exception would be the Norfolk & Western, which held out on scrapping its steam fleet until the late 1950s).

And this is one reason for the locomotive's astronomically high sales numbers. Not only was it a practical, useful, and reliable model like the GP7 but it also helped those lines that had to fully dieselize do so

78005761747156298860970938.jpgChicago, Burlington & Quincy GP9 #288 is seen here at work in Kansas City, circa 1965. American-Rails.com collection.

Not surprisingly, with the success of the GP9 and GP7 series the units could be found on all types of railroads (both large and small) and in all types of service (main lines, spurs, branch lines, yards, etc.).

Of course, the 3,400+ units listed above includes only those U.S. companies that bought the GP9. Since 1949 EMD had established its Canadian division, General Motors Diesel (GMD) that saw a few hundred sales of the GP7 just after opened although sales really took off for the GP9.

Ten different Canadian lines purchased 646 examples of the locomotive including; Algoma Central Railway (2), Canadian National (349), Canadian Pacific (200), Quebec Cartier Mining (9), Midland Railway Company of Manitoba (1), New York Central for its Canadian operations (12), Northern Alberta Railways (10), Ontario Northland Railway (6), Quebec North Shore & Labrador Railway (54), and Toronto, Hamilton & Buffalo Railway (3). 

285209350927437298390479038.jpgPennsylvania GP9B #3808-B (built as #7183-B) and GP9 #7269 at East Peoria, Illinois, circa 1967. American-Rails.com collection.

Data Sheet

Entered Production1/1954 (Milwaukee Road #2400)
Years Produced1/1954 - 10/1959 (12/1959 for GP9B)
Engine BuilderGM
Length56' 2"
Height (Top Of Rail To Top Of Cab)14' 6"
Width10' 3"
Weight249,000 Lbs
Fuel Capacity800 Gallons
Air CompressorGardner-Denver
Air Compressor ModelWBO
Air Brake ManufacturerWestinghouse
Air Brake Schedule24RL
Truck TypeBlomberg
Truck Wheelbase9'
Wheel Size40"
Traction MotorsD37 (4), GM
Primary GeneratorD12B, GM
Auxiliary GeneratorDelco (64-72)
MU (Multiple-Unit)Yes
Dynamic BrakesYes
Gear Ratio62:15
Tractive Effort (Starting)62,750 Lbs at 25%
Tractive Effort (Continuous)44,600 Lbs at 9.3 mph
Top Speed65 mph

Production Roster

Owner Road Number(s) Quantity Date Built
Baltimore & Ohio675-696, 747-752, 3413-3425, 6447-65981931955-1958
Bangor & Aroostook76-8051954
Belt Railway Of Chicago471, 480-48131956-1958
Boston & Maine1700–1749501957
Butte, Anaconda & Pacific Railway104-10741957
Central Of Georgia160-170, 1040-1042141954-1957
Central Railroad Of New Jersey1531-153221959
Central Vermont Railway4923-4929, 4547-4557181957
Chesapeake & Ohio5901-62633631954-1957
Chicago & Eastern Illinois221, 229, 233-23881956-1958
Chicago & North Western1711-1720, 1725-1773591954-1959
Cleveland Union Terminal (NYC)5900-590341954
Clinchfield Railroad917-91821956
Denver & Rio Grande Western5901-5904, 5911-5914, 5921-5924, 5931-5934, 5941-5944, 5951-5954241955-1956
Detroit, Toledo & Ironton980-992131955-1957
Electro-Motive (Demo)725711955
Erie Railroad1260-126561956
Florida East Coast651-676261954-1957
Georgia Railroad1040-104231954
Grand Trunk Western1751-1767, 4134-4139, 4442-4450, 4539-4546, 4558-4559, 4902-4922, 4930-4933671954-1959
Great Northern656-734791954-1959
Illinois Central9000-9257, 9300-93893481954-1959
Kansas City Southern163-16531959
Lehigh Valley300-30121959
Louisville & Nashville437, 441-459, 515-522, 553-554301954-1958
Meridian & Bigbee Railroad10211957
Midland Valley Railroad152-15321958
Milwaukee Road280-331, 2368-24431281954-1959
Minneapolis & St. Louis Railway600-608, 700-713231956-1958
Mississippi Export Railroad6011957
Missouri Pacific1131-1144, 4332-4371541955-1959
New Haven1200-1229301956
New York Central5904-6028, 6041-60751601954-1957
Nickel Plate Road448-534, 800-8141021955-1959
Norfolk & Western10-13, 506-521, 620-699, 714-9143011955-1959
Northern Pacific200-3751761954-1958
Pennsylvania7175B-7204B, 7230B-7239B (GP9B)401957-1959
Phelps Dodge Corporation21-23, 30-43171955-1957
Rock Island1312-1332211957-1959
Santa Fe700-751521956-1957
Seaboard Air Line1900-1929, 1954-1979561955-1959
Soo Line400-414, 550-558, 2400-2413 (Wisconsin Central), 2550-2556 (Wisconsin Central)451954-1957
Southern Pacific240-249 (Texas & New Orleans), 280-283 (T&NO), 400-458 (T&NO), 5600-5719, 5730-5844, 5872-58913181954-1959
Southern Railway (Including Subsidiaries)302-303, 2500-2501, 6245-6249, 6898-6899, 8214-8215131955-1956
Spokane, Portland & Seattle150-15561956
St. Louis Southwestern Railway (Cotton Belt/SP)820-831121957-1959
Texas & Pacific (MP)1131-1144141957-1959
Texas-Mexican Railway (Tex-Mex)85311958
Union Pacific130-248, 250-3492191954-1957
Union Pacific130B-204B, 300B-349B (GP9B)1251954-1957
Wabash Railroad484-495121954-1956
Western Pacific725-73281955
Western Maryland25-45211954-1957
Western Railway Of Alabama530-53121954
Winston-Salem Southbound Railway1501-150441957

Rio Grande GP9 #5921 at Pueblo, Colorado during the 1970s. American-Rails.com collection.

It should also be noted that there were buyers for the GP9B although it sold very like like with the GP7B; the Pennsylvania Railroad bought 40 while Union Pacific purchased 125.

The units’ extreme versatility is, of course, what made them so successful, and many continue to be found today in freight service on both short lines and regionals (as well as museums and tourist lines).

Spotting them, however, can be a bit tough, as most have been rebuilt at some point in the last 50 years, sometimes altering their looks a bit.

Be on the lookout, however, and you can find them! The GP7 and GP9 models were only the beginning of the series and later four-axle, as well as six-axle, models would follow. 


  • Marre, Louis A. Diesel Locomotives: The First 50 Years, A Guide To Diesels Built Before 1972.  Milwaukee: Kalmbach Publishing Company, 1995.
  • Pinkepank, Jerry A. Diesel Spotter's Guide.  Milwaukee: Kalmbach Publishing Company, 1967.
  • Schafer, Mike. Vintage Diesel Locomotives. Osceola: MBI Publishing, 1998.
  • Solomon, Brian. American Diesel Locomotive, The. Osceola: MBI Publishing, 2000.
  • Trzoniec, Stanley W.  Vintage & Modern Diesel Locomotives: Prime Movers Of America.  Minneapolis:  Voyageur Press, 2015.
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