EMD "GP20" Locomotives: Data Sheet, Specs, Roster

Last revised: December 16, 2024

Electro-Motive's GP20 was the builder's first turbocharged model in the General Purpose series. Interestingly, it was inspired by Union Pacific's efforts to turbocharge the 567 prime mover.

It was also the first road-switcher offered with a standard low nose/hood, designed to provide crews greater forward visibility. EMD would later refine its look on the GP30.

The builder eventually came up with the Spartan Cab on the GP35 that employed these concepts while sporting a pointed, low nose.

When production had ended on the GP20 a little more than a half-dozen domestic railroads purchased more than 200 examples. Today, this resilient little road-switcher can still be found in operation on numerous short lines 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.

Photos

An Electro-Motive photo featuring GP20 demonstrator #5625 in August, 1960. This locomotive, along with demonstrators #5626-5628, were all sold to Southern Pacific (#7234-7237).

Overview

In essence, the GP20 was merely a turbocharged GP18. In his book, "Diesel Locomotives: The First 50 Years," author Louis Marre notes the model's genesis began with Union Pacific's belief that the 567C powerplant could be turbocharged.

In September, 1955 UP added 9 AiResearch and 10 Elliott turbochargers to its own GP9s, boosting their horsepower output to 2,000, in an effort to prove such technology could be effectively applied to the 567.

These locomotives were dubbed Omaha GP20s. After the experiment proved successful, the railroad reverted 15 back to normally aspirated GP9s while 4 others were reengined with newly turbocharged EMD prime movers.

Electro-Motive held considerable reservations to UP's turbocharging efforts as it feared doing so would lead to higher maintenance costs. However, western railroads were pushing for higher horsepower variants, especially Union Pacific. Following UP's successful tests the builder decided to catalog a new, standalone turbocharged model.

Prior to this EMD had rebuilt nine other Union Pacific GP9s with turbocharged 567D2 engines between March and June, 1959. These included numbers 300, 301, 305, 311, 313, 320, 300B, 301B, and 308B.

In addition, EMD rebuild 47 others, which retained their 567Cs, with turbochargers. Also dubbed as Omaha GP20s these locomotives were completed between June, 1959 and October, 1965.

Santa Fe GP20 #3028 in the "Kodachrome" livery; summer, 1986. Location not listed. Author's collection.

Specifications

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.

Marty Bernard caught CB&Q GP20 #919, a GP30, an SD24, and another GP20 leads a long freight at the Oak Street Bridge overpass in Hinsdale, Illinois on April 28, 1963.

Spotting Features

In his book, "Diesel Locomotives: Cyclopedia, Volume 2," author Bob Hayden notes that only the first ten GP20s built for Western Pacific (#2001-2010), as well as thirty six others for Great Northern (built to operate long hood forward), featured EMD's classic high, short hood.

The remainder sported the new low, short hood with a slight downward slope for greater forward visibility. Aside from this trademark, the only distinguishing feature from the earlier GP7 through GP18 was the addition of a short, rectangular turbocharger exhaust stack located just behind the first exhaust fan near the cab.

While not unique solely to the GP20, one cosmetic feature found on few other EMD designs was a solid front windshield.

It was first applied to the four-axle GP18, and could also be found on early Special Duty models like the SD18 and SD24. By the GP30's release in 1961 the builder had changed the styling to a split version.

Data Sheet

Entered Production	11/1959 (Western Pacific #2001-2006)
Years Produced	11/1959-4/1962
Engine	567D2
Engine Builder	GM
Horsepower	2000
RPM	800
Cylinders	16
Length	56' 2"
Height (Top Of Rail To Top Of Cab)	14' 6"
Width	10' 0"
Weight	240,000 Lbs
Fuel Capacity	900 Gallons
Air Compressor	Gardner-Denver
Air Compressor Model	WBO
Air Brake Manufacturer	Westinghouse
Air Brake Schedule	24RL
Trucks	B-B
Truck Type	Blomberg
Truck Wheelbase	9'
Wheel Size	40"
Traction Motors	D47 (4), GM
Primary Generator	D22, GM
Auxiliary Generator	Delco (64-72)
Alternator	D14
MU (Multiple-Unit)	Yes
Dynamic Brakes	Yes
Gear Ratio	62:15
Tractive Effort (Starting)	64,000 Lbs at 25%
Tractive Effort (Continuous)	45,000 Lbs at 9.3 mph
Top Speed	65 mph

Production Roster

Total Built = 260

Owner	Road Number(s)	Serial Number(s)	Order Number	Completion Date
Great Northern	2000-2011	25561-25572	7583	4/1960
Santa Fe	1100-1124	25573-25597	7584	5/1960-7/1960
Western Pacific	2001-2006	25623-25628	5607	11/1959
Great Northern	2012-2017	25700-25705	7583	4/1960
Western Pacific	2007-2010	26041-26044	7592	7/1960
Union Pacific	700-729	26045-26074	5624	7/1960-8/1960
Electro-Motive (Demonstrator)	5625-5628 (became Southern Pacific #7234-7237)	26107-26110	5625	8/1960
Great Northern	2018-2024, 2035, 2025-2034	26286-26303	7594	11/1960-12/1960
St. Louis Southwestern Railway (Cotton Belt)	800-809	26304-26313	7595	12/1960-1/1961
Chicago, Burlington & Quincy	900-901	26571-26572	7598	2/1961
Chicago, Burlington & Quincy	902-935	26573-26606	7597	2/1961-4/1961
New York Central	6100-6103	26815-26818	7606	7/1961
New York Central	6104-6114	26819-26829	7607	7/1961-8/1961
Santa Fe	1125-1174	26831-26880	7609	8/1961-12/1961
St. Louis Southwestern Railway (Cotton Belt)	810-819	26943-26952	7611	12/1961-1/1962
Southern Pacific	7200-7223	27087-27110	5634	1/1962-3/1962
Southern Pacific	7224-7233	27345-27354	5634	3/1962-4/1962

Western Pacific GP20, #2001, and a number of other Geeps pull a freight through the Niles Canyon near Sunol, California during August of 1969. Drew Jacksich photo.

Interestingly, of all the GP20s produced, only New York Central's 15 examples were built without dynamic brakes. The railroad felt the feature was unnecessary along its Water Level Route main line which contained few notable grades.

Buyers of the locomotive included the Santa Fe (75), Burlington (36), Great Northern (36 high hoods), New York Central (15), Southern Pacific (38, which included demonstrators 5625-5628), Cotton Belt (20), Union Pacific (30, purchased new), and Western Pacific (10 high hoods).