An EMD SW1200 is a four-axle diesel switcher locomotive built by General Motors Electro-Motive Division between January 1954 and May 1966.

Additional SW1200 production was completed by General Motors Diesel in Ontario, Canada, between September 1955 and June 1964.

Most of the locomotive's external features were unchanged from the SW9, making distinguishing between the two models difficult.

[1] A few units were built with dynamic brakes, featuring a large square box with a fan on top of the hood, right in front of the cab.

An SW1200RS (RS for road switcher) is a variation of the standard SW1200 that features large front and rear (on some units) numberboard housings, EMD Flexicoil B-B trucks, and larger fuel tanks for road switcher service.