As part of “Operation Phoenix”, the Victorian Railways wanted to significantly expand passenger services on rural branch lines after the end of the Second World War. Three versions of diesel railcars were ordered, which were designated by their engine power. The power sections were each built by the British company Walker with diesel engines from Gardner. The associated trailers were manufactured in Australia using a lightweight construction method and designed for a service life of just ten years. The basic structure of the car bodies was made of steel and wood and was clad in aluminum.
The two smaller versions had a two-axle power section, basically constructed like a semitruck, each containing a six-cylinder diesel engine and a driver's cab. 13 examples of the 102 hp version and 12 examples of the 153 hp version were manufactured. One railcar of the weaker version was only intended as a reserve and did not have an associated trailer. The trailers usually held 18 first class and 22 second class passengers and two tons of luggage. Some trailers had five additional seats in second class and a smaller luggage compartment. Since there was only one driver's cab, the vehicles had to be turned at the end of the route.
The heaviest version consisted of a central power module with two eight-cylinder engines and two attached trailers, each with a luggage compartment, a passenger compartment and a driver's cab. While on one side there were 38 seats in first class, on the other side there were 56 seats in second class. It was possible to move from one part to the other while driving. A total of twelve sets were made from this version.
The trailers of the variants with 102 and 153 hp were initially assigned to one power section each, but were freely exchanged with each other as part of routine inspections and repairs. The 280 hp railcars could exceed their scheduled top speed of 60 mph or 97 km/h on longer stretches. However, the lightweight construction got evident in the fact that many repairs had to be made to the car bodies after just a few years. Nevertheless, the intended service life was significantly exceeded, so that the first few sets only had to be retired from 1970. Only between 1977 and 1980 was the rest of the fleet retired. Today there is still a set with 153 hp and one with 280 hp, the latter having been certified for use again since 1990.
