EMD GP20

EMD GP20
Type and origin
Power typeDiesel-electric
BuilderGeneral Motors Electro-Motive Division (EMD)
ModelGP20
Build dateNovember 1959 to April 1962
Total produced260
Specifications
Configuration:
 • AARB-B
 • UICBo′Bo′
Gauge4 ft 8+12 in (1,435 mm)
Length56 ft 2 in (17.12 m)
Width10 ft 3 in (3.12 m)
Height14 ft 6 in (4.42 m)
Loco weight240,000 lb (108,862 kg)
Fuel capacity2,350 US gal (8,896 L; 1,957 imp gal)
Lubricant cap.227 US gal (859 L; 189 imp gal)
Coolant cap.220 US gal (833 L; 183 imp gal)
Sandbox cap.18 cu ft (0.51 m3)
Prime moverEMD 16-567D2
Engine typeTwo-stroke V16 diesel
AspirationTurbocharged
Displacement9,072 cu in (148.66 L)
GeneratorEMD D-22
Traction motorsEMD D47 (4) or D57 (4)
Cylinders16
Cylinder size8+12 in × 10 in (216 mm × 254 mm)
TransmissionDiesel electric
Loco brakeSchedule 24RL or 26L Straight air, optional: dynamic
Performance figures
Maximum speed65 mph (105 km/h)
Power output2,000 hp (1.5 MW)
Tractive effortStarting: 63,375 lbf (28,746 kgf) Continuous: 45,000 lbf (20,412 kgf) @9.3 mph (15.0 km/h)
Career
LocaleUnited States

The EMD GP20 is a 4-axle diesel-electric locomotive built by General Motors' Electro-Motive Division between November 1959 and April 1962. Power was provided by an EMD 16-567D2 16-cylinder turbocharged engine which generated 2,000 horsepower (1,500 kW). EMD was initially hesitant to turbocharge their 567-series diesel engine, but was spurred on to do so following successful tests made by Union Pacific in the form of UP's experimental Omaha GP20 units. 260 examples of EMD's production locomotive model (with the EMD turbocharger) were built for American railroads.

The GP20 was the second EMD production locomotive to be built with an EMD turbocharged diesel engine, sixteen months after the six-axle (C-C) model SD24. Power output of the turbocharged SD24 was 33 percent higher than the 1,800 hp (1,340 kW) of the concurrent Roots blower-equipped SD18s with the same engine displacement, 400 hp (298 kW) per axle, but the power output of the turbocharged GP20 was only 11 percent higher than the 1,800 hp (1,340 kW) of the concurrent Roots blower-equipped GP18s with the same engine displacement 500 hp (373 kW) per axle, due to the limitations of the traction motors then available. Nevertheless, the turbocharged GP20 provided full rated power at all altitudes, which the Roots-blown GP18 could not provide.