The WA class were originally coded as _WX_. In 1963, the code conflicted with the introduction of letter 'X' indicating bogie exchange and so the class was relettered to WA. The tanks were used to carry the weed spray chemical. A train of tanks and a weed spray vehicle travelled all the lines of the system spraying the tracks to kill weeds. The spray cycle seems to have been about three years.
The number group was 1 - 9, 20 - 25. Numbers 10 - 19 were WX vehicles scrapped prior to WA reclassification.
The fleet of tanks in active service was reduced to WA 1 to 9. The remaining four wheelers were scrapped or stored with the exception of WA 22 . Several of the WA's in the group 1 - 9 were fitted with replacement underframes in the late 1970's. This work was done at Bendigo Workshops with an ELX_ design underframe being used.
WA 22 became a liquid fertiliser tank. Manure that was washed out of cattle trucks at the Brooklyn Livestock Sidings was transported away for disposal. During the late 1970's it was given routine maintenance and the pump was moved from top of the tank to one side down on the underframe.
Of the various types of WX tank wagons, two types became WA:
Were bogie tankers with _E__ bogie open wagon underframes
Were four wheel tank wagons