EMD SW1


The EMD SW1 is a diesel-electric switcher locomotive built by General Motors' Electro-Motive Corporation between December 1938 and November 1953. Final assembly was at EMD's plant at LaGrange Illinois. The SW1 was the second generation of switcher from EMD, succeeding the SC and SW. The most significant change from those earlier models was the use of an engine of EMD's own design, the then-new 567 engine, here in V6 form. 661 locomotives of this design were built, no SW1s were built after March 1943 until production started again in September 1945.

Engine and powertrain

The SW1 introduced a 6-cylinder version of the 567 series engine to EMC/EMD switchers. Developing at 800 rpm., this engine remained in production until 1966. Designed specifically for railroad locomotives, this was a supercharged 2 stroke 45 degree V type, with an, bore by stroke, giving displacement per cylinder. A D.C. generator provides power to four motors, two on each truck, in a B-B arrangement. The SW1, like most EMD switchers, use the AAR Type A switcher truck. EMC/EMD has built all its own components since 1939.

Production changes

A number of changes were made to the SW1 over its production life. Internally, the post-war locomotives used the 567A engine.
Externally, the two center cab windows over the hood, which were curved to follow the roofline originally, but became flat-topped after mid-1950. Another external difference is the taper of the hood to the cab, which was a two-stage taper in earlier units but became a single taper in later production. Very early locomotives were delivered with a stubby exhaust stack, but this did not lift the diesel exhaust sufficiently clear of crew visibility. All later units were delivered with EMD's standard conical switcher stack, while early units were generally modified with taller stacks too. Early locomotives had a single large headlight, while later had twin sealed-beam headlights.

Original owners