An EMD GP60 is a 4-axle (B-B) diesel-electric locomotive built by General Motors Electro-Motive Division between 1985 and 1994. The GP60 was EMD's first engine that was classified as a "third-generation" locomotive. Hidden behind the electrical cabinet doors on the rear wall of the cab, the GP60 concealed a trio of microprocessors that monitored and managed a host of engine, cooling system and control functions. The engine's on-board microprocessors replaced hundreds of wiring circuits, dozens of relays and all but one module card, making it an improvement among EMD's engines.