The GP40 is a 4-axle diesel-electric road-switcher locomotive built by General Motors, Electro-Motive Division between November 1965 and December 1971. It has an EMD 645E3 16-cylinder engine generating 3,000 hp (2,240 kW).The GP40 is 3 feet (0.914 m) longer than its EMD 567D3A-engined predecessor, the GP35, and distinguished visually by its three 48-inch radiator fans at the rear of the long hood, while the GP35 has two large fans and a smaller one in between.