The EMD SDP40F was a six-axle 3,000 hp (2.2 MW) C-C diesel–electric locomotive built by General Motors Electro-Motive Division (EMD) from 1973–1974. Based on Santa Fe’s EMD FP45, EMD built 150 for Amtrak, the operator of most intercity passenger trains in the United States. Amtrak, a private company but funded by the United States government, had begun operation in 1971 with a fleet of aging diesel locomotives inherited from various private railroads. The SDP40F was the first diesel locomotive built new for Amtrak and for a brief time they formed the backbone of the company's long-distance fleet.