There were three wagons in this class, numbered QAB 1, 2 and 3. They were converted from _Q__ flat wagons, of the style built from 1915 onwards. QAB 1 was converted from Q 77 in 1963 and was known as QAB 77 until 1964 when the other two Q wagons were modified to the same design.
Traffic was from the Rosedale "Pyneboard" factory to Melbourne. In the late 1960's with increased traffic, a batch of four wheel wagons coded KAB_ wagons were introduced to service.
Wooden slats were placed along the floor length to support the load evenly.
In the 1979 recoding they were to be classed as VFCA but at the time the wagons in storage. The wagons were scrapped in 1981 without recoding.