The SD40T-2 is a model of diesel-electric locomotive built by General Motors Electro-Motive Division in the United States. The SD40T-2 is equipped with a 16-cylinder EMD 645E3 diesel engine producing Template:Convert. 312 SD40T-2s were built for three railroads in the United States between April 1974 and July 1980. This locomotive and the SD45T-2 are popularly called tunnel motors, but EMD's term is SD40-2 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 air intakes are located lower down at the rear of the locomotive.
8300 series featured extended "snoot" noses for radio control equipment. 8278 was damaged beyond repair in the 1989 Cajon Pass runaway and sold for parts, then scrapped.