The SD45 is a six-axle diesel-electric locomotive built by General Motors Electro-Motive Division between December, 1965, and December, 1971. It had an EMD 645E3 twenty-cylinder engine generating 3,600 hp (2,680 kW) on the same frame as the EMD SD38, EMD SD39, EMD SD40, and EMD SDP40.1,260 were built for American railroads before the SD45-2 replaced it. Other models, like the SD45T-2 'Tunnel Motor', were released in 1972.SD45s had several teething problems.