An SD9 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between January 1954 and June 1959. An EMD 567C 16-cylinder engine generated 1,750 horsepower (1.30 MW). Externally similar to its predecessor, the SD7, the SD9 was built with the improved and much more maintainable 567C engine. Four hundred and seventy-one SD9s were built for American railroads, while a further 44 were produced for export.