An SD40T-2 is a 6-axle road switcher diesel-electric locomotive built by General Motors Electro-Motive Division having a 16-cylinder EMD 645E3 diesel engine producing 3,000 horsepower (2,240 kW). 312 SD40T-2s were built for North American railroads between April 1974 and July 1980. This locomotive and the SD45T-2 are popularly called tunnel motors, but EMD's term is SD40-2s with "cooling system modifications" because they were designed for better engine cooling in mountainous areas.^[1] The difference between this locomotive and its non-tunnel motor cousin, the SD40-2, are the radiator intakes and radiator fan grills located at the rear of the locomotive.


(Photos from Wikipedia)