Rail motors consisting of a single self-contained passenger carriage and engine unit were an obvious idea for reducing the cost of operating passenger service on more lightly patronised lines. The first vehicles of this type used on the Victorian Railways were two Rowan steam cars introduced in the 1880s. In 1911, two petrol-powered McKeen rail motors were imported from America. With distinctive streamlined bodies and round porthole style windows they cut a striking appearance, but were under-powered and not technically successful.

Shortly after the First World War, the Newport Workshops began building a series of petrol rail motors based on AEC truck chassis and engine units. Despite primitive open-sided passenger compartments and wooden bench seating they proved a success, with some 20 units in service on country branchlines by the mid 1920s. From 1925, Newport also built a number of improved double-ended rail motors with dual driver controls that avoided the need to turn vehicles for return journeys. They were the first diesel-powered vehicles used on the Victorian railways.

Between 1948 and 1950, new improved English-built Walker diesel rail motors were introduced with three standard sized units having seating for 40, 45 and 94 passengers respectively. Painted in the distinctive 'blue and gold' VR livery, they remained the mainstay of passenger services on many country lines until the late 1970s.