The RP20BD is a diesel-electric switcher locomotive built by Railpower Technologies. It is a "genset" locomotive, having three engine-generator sets.
The engines are computer controlled, with the computer stopping and starting engines on a rotating basis, as required to produce the horsepower needed at any given moment.
RP20BDs are rebuilt from older locomotives such as the General Electric Dash 7 series and EMD General Purpose series.
References
