EMD E-units were a line of passenger train diesel locomotives built by the General Motors Electro-Motive Division (EMD) and its predecessor the Electro-Motive Corporation (EMC). Final assembly for all E-units was in La Grange, Illinois. Production ran from May 1937, to December, 1963. The name E-units refers to the model numbers given to each successive type, which all began with E. The E originally stood for eighteen hundred horsepower (1300 kW), the power of the earliest model, but the letter was kept for later models of higher power.