The GP20 debuted in 1959 and remained in Electro-Motive's catalog through 1962. It was the first model
of what is commonly referred today as second-generation diesels, or those
designs that are clearly distinguished from earlier models with less
horsepower and fewer other technological features. The GP20 was one of
EMD’s first to feature a low,
short hood which became a standard feature on future models over the next 30+ years (until the FRA mandated that the wide "safety" cab 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 experiment considered a resounding success the builder decided to catalog the turbocharger in a brand new model. The GP20 came equipped with dynamic brakes as a standard option (a system for temporarily employing traction motors as generators and using the resulting electromotive force to slow the train) and offered oil-bath filters to keep 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; 64,000 pounds starting effort and 45,000 pounds
continuous. While the locomotive was not as successful as its later counterparts such as
the GP30, GP40/-2, and 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 the late GP30 was the latter’s distinctive bulge
over the cab where the dynamic braking was housed (a cosmetic feature only) and a solid front
windshield as opposed to a split version on the GP30.
EMD GP20 Production Roster
|New York Central||6100-6114||15||1961|
|St. Louis Southwestern Railway (Cotton Belt/SP)||800-819||20||1960-1962|
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 where 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.
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