E.B.T M-1 Doodlebug (rail car)

The development of gasoline engines led railroads to seek it as a higher efficiency alternative to steam power for low-volume branch line services at the start of the 20th century. The McKeen railmotor was a line of self-propelled gasoline-driven railcars produced between 1905 and 1917. The 200 HP motor on the 55-foot long or 70-foot long units drove only one set of wheels, and the lack of power and traction, the unreliability of their transmissions, and an inability to reverse, were major limitations. General Electric (“GE”) was the pioneer of gas-electric railcars: GE in February, 1906 rebuilt a wood passenger coach into a gas-electric unit which was placed in trial service on the Delaware and Hudson Railroad. The St. Louis–San Francisco Railway was an early adopter of this technology, placing an initial order for ten gas-electric units in 1910 and seven additional by 1913, giving it the distinction of having the largest fleet of gas-electric motor cars in the country. The petroleum-electric drive control system invented in 1914 by Hermann Lemp, an engineer with GE, became the technological foundation of self-propelled gasoline railcars in the 1920s.

In 1923 the Electro-Motive Company began production of self-propelled railcars, subcontracting bodies to the St. Louis Car Company, prime movers to the Winton Engine Company, and electrical equipment to General Electric. The Pullman Company was subsequently added as a subcontractor for car bodies. Improvements to railcars were sought by The Pullman Company, who experimented with lightweight designs in partnership with the Ford Motor Company in 1925, then enlisted the services of pioneering all-metal aircraft designer William Bushnell Stout in 1931 to adapt airplane fuselage design concepts to railcars. In 1931 the Budd Company entered a partnership with the French tire company Michelin to produce lightweight stainless steel Budd-Michelin railcars in the US. Those advances in lightweight railcar design were an important step in the development of the lightweight diesel-electric streamliners of the 1930s.