The diesel-electric hybrid locomotive was developed to run electric motors powered by the onboard 7FDL-12 diesel engine or from 3rd rail supplying 750 volts of direct current (DC) and can switch between modes while underway. The P32AC-DM is equipped with AC (alternating current) traction motors converting the third-rail DC supply on board.
Metro-North Railroad and the Connecticut Department of Transportation (Metro North Equipment Pool) use the P32AC-DM as it is the ideal locomotive for hauling passenger trains from non electrified regional suburban areas to New York City where diesel locomotives are prohibited from entering the Park Avenue Tunnel.
P32AC-DM locomotives are geared for 110 mph running, however they are restricted to 60 mph in 3rd rail territory due to arcing and flashing of the electrical contact shoes.