Hoodlebug was a nickname used for small passenger trains or trolley cars that provided commuter service in parts of the United States. The name usually applies to such service in rural areas between towns or from towns to factories or mines before the advent of bus service. Hoodlebugs were also used for school students before the widespread use of school buses.
It appears this is a local vernacular term limited to mid-Atlantic and Midwestern states. Its etymology is uncertain, but it may be a variation of doodlebug, a railroad term for certain types of small, self-propelled cars.
Vehicles that provided similar rail service in parts of the western United States were often referred to as Galloping Geese. However, most galloping geese were converted street vehicles while most hoodlebugs were converted trolleys.