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Road-Specific
Detailing
- Five-Pole Skew-Wound
Armature Motor
- 14:1 Gear Ratio for Easy
Multiple Unit Operation
- Machined Brass Flywheels
- All-Wheel Drive
- Precisely Meshed Helical
Gears for Silent Running
- Constant &
Directional Headlights
- Heavy Die Cast Chassis
for Maximum Traction
- Proto MAX(TM) Metal
Knuckle Couplers
- Factory-Installed Sound
& DCC
By the mid 50s, increasing
pressure from long-haul trucks, declining passenger
revenues and mounting costs forced western
railroads to find new ways to improve service.
Faced with expensive overhauls of early cab and
hood unit diesels, many began looking at new
equipment as well as ways to improve existing
motive power. In 1955 Union Pacific equipped
several GP9s with turbochargers as an experiment.
Their success inspired EMD to create its own
turbocharger for the 567 prime mover, leading to
the introduction of the six-axle SD24 in 1958.
Further experiments in 1959 created a four-axle
version, dubbed the GP20. Early in their careers,
the new units were typically assigned priority
freights that demanded higher speeds. With the
arrival of newer power, they were gradually bumped
into secondary runs, and eventually spent their
last years in local and yard service. Following
their retirement, a few went to work for shortline
operators. Western Pacific #2001, the very first
GP20, was donated by UP to the Feather River Rail
Society in 1985, where it has been restored to its
as-built appearance.
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