In the United States, doodlebug or hoodlebug is a name for a type of self-propelled railcar most commonly configured with both a passenger and freight compartment. Early models were usually powered by a gasoline engine, with either a mechanical drive train or a generator providing electricity to traction motors. After a number of years of service, it was common for doodlebugs to be repowered with a diesel engine. Doodlebugs sometimes pulled an unpowered trailer car, but were more often used singly. They were popular with some railroads during the first part of the 20th century to provide passenger and mail service on lightly used branch lines at less expense than with a trainconsisting of a locomotive and coaches. Several railroads, mostly small regional and local networks, provided their main passenger services through doodlebugs in a cost-cutting effort.
History
The development of gasoline engines led railroads to seek it as a higher efficiency alternative to steam power for branch line services at the start of the 20th century. The McKeen railmotor was a line of gasoline-driven railcars produced between 1905 and 1917. The success of these early efforts was limited by the unreliability of their mechanical drive systems and the limited power available from early gasoline engines. Electric trolley cars were preferred for interurban service. The petroleum-electric drive control system invented in 1914 by Hermann Lemp, an engineer with General Electric, 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 companyMichelin 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. Production of self-propelled railcars dropped off with the onset of the Great Depression, which hurt the market for branch line services. But production was revived in 1949 with introduction of the Budd Rail Diesel Car. The variant name hoodelbug was largely limited to the mid-Atlantic states, particularly Pennsylvania. A major hiking trail in Indiana County, Pa., is named Hoodlebug Trail.
