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The EMD GP20, The Beginning of Second-Generation Power

The Electro-Motive Division's (EMD) GP20 was essentially the builder’s first entry into what is now considered second-generation diesels. To some extent the locomotive was an experimental design that offered a turbocharged version of EMD's very successful model 567 prime mover, which proved to be moderately successful. It was also the first road switcher model that EMD offered exclusively with a low nose/hood that tapered away from the cab (the builder would refine this design in the later GP30 model to remain flush its entire length away from the cab). When production had ended on the GP20 a little more than a half-dozen American Class I railroads purchased more than 200 examples of the model. Today, this resilient little road switcher can still be found in operation on numerous shortlines are the country. Additionally, at least two are known to be officially preserved; Southern Pacific #7207 used by the Blue Ridge Scenic Railway and Western Pacific #2001 at the Western Pacific Railroad Museum.

The GP20, which debuted in 1959 and built through 1962 was EMD’s first model of what is commonly referred today as second-generation power, or those diesel locomotives that are clearly defined from early models with less horsepower and fewer other technological features. The GP20 was one of EMD’s first to feature the "standard cab," simply meaning the low, short hood which became a standard design feature with future models over the next 30+ years (until the FRA mandated that the wide "safety" cab design be employed on every new locomotive in the 1990s for added safety). The GP20's prime mover was EMD’s upgraded 567D2 turbocharged engine, which significantly increased horsepower from earlier models.

Interestingly, the idea for the GP20 came from an experimental test by Union Pacific. Using nine of its GP9s the railroad added a turbocharger to boost their horsepower rating to 2,000 dubbing the locomotives Omaha GP20s. The idea turned out a huge success despite EMD's reservations about adding the feature to its prime mover. With the successful test the builder decided to simply catalog the design as new model. As with all earlier models EMD had released up until 1959 the GP20 came equipped with dynamic brakes (a system for temporarily employing traction motors as generators and using the resulting electromotive force to slow the train) and offered oil-bath filters that kept out dust, dirt, and other particles from reaching internal components, a relatively new concept for its time. The GP20 offered tractive effort ratings similar to the earlier GP18, which was a slight increase above the GP7 and GP9 models; 64,000 pounds starting effort and 45,000 pounds continuous.

While the GP20 was not as successful as its later sisters such as the GP30, GP40, GP40-2, and SD40/SD40-2 it nevertheless had decent sales for only being in the catalog for three years and cranked out a total of 260 units. Of note, railroads like the Western Pacific and Great Northern purchased theirs with the standard high hood found on the GP18s, GP9s, and GP7s. Perhaps the key visual differences between the GP20 and its later sister, the GP30, was the latter’s distinctive bulge over the cab where the dynamic braking was housed and a solid front windshield as opposed to a split version on the GP30.

Buyers of the locomotive included the Santa Fe (75), Burlington (36), Great Northern (36, high hoods), New York Central (15), Southern Pacific (34), Cotton Belt (20), Union Pacific (30), WP (10, high hoods). Additionally, EMD's four demonstrators, 5625–5628, went to Southern Pacific. Places one can still find GP20s in operation today include the Georgia Midlands Railroad, RJ Corman, Lycoming Valley Railroad, Georgia Northeastern, Alabama & Tennessee River, Decatur Junction Railway, Georgetown Railroad, Central New England Railroad, Sierra Railroad, Keokuk Junction Railway, Peoria & Western, Kansas City Terminal, Massachusetts Central, Arizona Eastern Railway, Fort Smith Railroad, Georgia Southern, and the Toledo, Peoria & Western. For technical data regarding the EMD GP20 please click here. Also, for information about EMD's GP series please refer to the chart below.

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Electro-Motive Division's "General Purpose" Road Switchers

Model Type	Units Built	Date Built	Horsepower
BL2	58	1948-1949	1,500
GP7	2,729	1949-1954	1,500
GP9	4,115 A Units/165 B Units (Calfs)	1954-1963	1,750
GP15-1	310	1976-1982	1,500
GP15T	28	1982-1983	1,500
GP18	405	1959-1963	1,800
GP20	260	1959-1962	2,000
GP30	948	1961-1963	2,250
GP35	1,333	1963-1966	2,500
GP38	706	1966-1971	2,000
GP38-2	2,215	1972-1986	2,000
GP38-2W	51 (Built For CN)	1973-1974	2,000
GP39	23	1969-1970	2,300
GP39-2	239	1974-1984	2,300
GP40	1,243	1965-1971	3,000
GP40P	13 (Built For NJ Transit)	1968	3,000
GP40X	23	1977-1978	3,000
GP40-2	1,121	1972-1986	3,000
GP40-2W	275 (Built For CN)	1972-1986	3,000
GP50	278	1980-1985	3,500
GP59	36	1985-1989	3,000
GP60	380	1985-1992	3,800

Thanks to Tony Fernandez for help with the information on this page.

For more information on the GP20 series consider Mike Schafer’s Vintage Diesel Locomotives which looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic EMDs, or diesels in general, this book gives an excellent general history of both.

You might want to also consider the book EMD Locomotives from author Brian Solomon. Solomon's book highlights the history of EMD from its earliest beginnings in the 1920s, to its phenomenal successes in the mid-20th century, and finally its decline into second spot behind General Electric in the late 20th century and eventual sale by General Motors in 2005. The book features 176 pages of EMD history and is filled with excellent photography and illustrations. If you're interested in perhaps purchasing either (or both) of these books please visit the links below which will take you to ordering information through Amazon.com, the trusted online shopping network.

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