The EMD SD40 is an American 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division between January 1966 and August 1972.

All shared standardized components, including the frame, cab, generator, trucks, traction motors, and air brakes.

18 customized SD40s were built for the Illinois Central Railroad as model SD40A, using the longer SDP45 frame, which allowed for a larger 5,000 gallon fuel tank.

Versions of the SD40 modified for the Australian loading gauge were sold to WAGR and Victorian Railways as their L and C classes respectively.

• Ex-Canadian National SD40 #5232 (built November 1971) has been purchased by The Vintage Locomotive Society on January 10, 2015, from Cando and the Central Manitoba Railway.

• Chesapeake and Ohio #7534 has been donated by CSX Transportation to the C&O Historical Society in Clifton Forge, Virginia.

The engine was meant to be used on the Buckingham Branch Railroad, which also operates out of Clifton Forge, however the unit spends quite a bit of time at the Historical Society's museum.

[5] • Ex-Santa Fe #5007 (built 1966 as ATSF 1707) is preserved at the Western America Railroad Museum in Barstow, California.

[6] • Santa Fe #5008 (built 1966 as ATSF 1708) is preserved at the Walt Disney Hometown Museum in Marceline, Missouri.

[8] • Western Maryland #7471 is owned by a private individual and currently leased to the Steam Railroading Institute in Owosso, Michigan.