In 1952 two 5500 gallon tankers were built for CALTEX by the Hume Steel. They were numbered 112 and 114 with a third wagon (113) following in 1953. In 1954 301-311 were added by Hoskins Engineering with 312 being the last to enter service in 1954. Numbers 305 and 312 were written off in 1972. The WAGR outline diagram is shown below.