In the United States, doodlebug was the common name for a self-propelled gas-electric railroad car. Such a coach typically had a gasoline powered engine which provided electricity to traction motors on the vehicle, which drove the axles.
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, obviating the need to operate conventional trains consisting of a locomotive and coaches.
The name Doodlebug was also later applied as a nickname to the V1 flying bomb
See also
Steam dummy
