The RP20BD is a diesel-electric switcher locomotive built by Railpower Technologies.

It is a "genset" locomotive, having three engine-generator sets.

[1] 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.

[2] RP20BDs are rebuilt from older locomotives such as the General Electric Dash 7 series and EMD General Purpose series.

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