Montana Western gasoline-electric railcar, 1923

In 2003 the American Society of Mechanical Engineers named the Montana Western 31 railcar - now preserved at the Mid-Continent Railway Museum in North Freedom, Wisconsin - an historic mechanical engineering landmark. It is the oldest surviving railcar of the type that used a gasoline (petrol) engine and electric generator for motion and is the oldest surving piece of EMD manufactured equipment.

The Montana Western 31's technical attributes included the innovative control system of Hermann Lemp, who worked as an engineer for General Electric. The 32-ton rail motorcar, which was originally named the Great Northern 2313, contains baggage and passenger sections. Its manufacturer, Electro-Motive Engineering Corp. of Cleveland, Ohio, sold the Great Northern 2313 in 1940 to Montana Western, which operated it on a short 20-mile (32 km) route between the towns of Conrad and Valier in Montana.