power car

plural power cars

1. A vehicle that propels, and commonly also controls, a passenger train or tram, often as the lead vehicle.

   The inner power cars are brake second class compartment coaches; the guard has means of both bell and two-way telephone communication with the driving compartment.

   1960 September, “Inter-city diesel units for the Hull-Liverpool service of the N.E.R.”, in Trains Illustrated, page 560

2. A vehicle equipped with machinery for supplying heat or electrical power to other parts of a train.