In 1949 brake van ZG18 (formerly coach AG18) was used as the basis for workmen's van VW6790. The following year it was rebuilt to become the first VS class scale adjusters van. Two further vans of this type were created in 1961 (VS5076) and 1962 (V5077). VS5076 and 6790 were written off in 1980. VS5077 survived until 1991. Two WAGR outline diagrams are shown below. I'm not sure but I think that the lower one may apply to VS6790.