In 1985, two organisations were running the Government rail system in Victoria: Country service/freight by Vline and Melbourne suburban service by Metrail. Both systems were running their own service wagons.
Vehicles in bogie and wheel transports for 'Met' use were part of the _HR_ group. In 1985, those vehicles were reclassed to VZMA and placed onto the 'Met' vehicle Register.
In 1987, Vline recoded some ballast wagons as VZMA, which must have caused some confusion.
The Metrail VZMA wagons were numbered 90 - 100. The HR wagons they were converted from were all bogie vehicle replacements for the original fixed wheel HR wagons with the same number.