In the late 1940's the railways expanded the railcar fleet. One group of railcars introduced were the 102hp, Walkers Ltd railcars. The vehicles were built in Australia by Martin & King, under licence to Walkers Ltd of England.
Thirteen units were built, numbered RM 1 to RM 13. The railcars featured a short power bogie and cab end with a trailer and cab section. This made the units double ended. They were generally called "102's" by crews and railfans.
The railcars entered service between 1948 and 1950. Within a few days of being delivered from the builders they were placed into service. At the time, Jolimont Workshops was the railmotor depot.
In 1955 a power unit only was built. This was RM 13. It seems to have been a replacement power unit which enabled other units to be released for maintenace.
Most were removed from service in the mid to late 1970's. One is running on the Castlemaine and Maldon preserved railway.