Bit of mystery with this class. The official records clearly show three vehicles in the class. The vans were 1, 2 and 3.
WMA 1 was converted from _B__ 247 in 1888. B 247 was ex Hobsons Bay stock. WMA 1 was scrapped in 1903.
WMA 2 was converted from _AB_ 45 in 1898. AB 45 was built by Phoenix Foundry in 1877. In 1906 it was scrapped and replaced by a new workmans sleeper _WS_ 23. WS 23 was recoded to _W__ 21 and was in service to the late 1970's.
WMA 3 was converted from the 1st _B__ 376 in 1898. B 376 was converted from _A__ 172 in 1889. A 172 was ex Hobsons Bay stock, of which no data is available. WMA 3 was recoded to the 2nd WS 82 in 1907. In 1910 it was recoded to W 80 which was scrapped in 1928.
There is a diagram for WMA 5, however there are no 'Register' entries for it. This appears to be a case of 'pre-empting' uncompleted work. Perhaps an incorrect number has been applied to the diagram for 'No.2' which was a conversion from an identical vehicle type built as 'AB 45'.
The vans seem to have been assigned to weighbridge fitters who travelled to locations maintaining weighbridges.