In the late 1960's when the _JX_ construction was underway, two wagons were built as FX wagons with four flour hoppers. Later construction of fifteen wagons gave the class a number group of 1 - 17. The wagons were to be coded 'CFX' but entered service with the FX code letters.
The main area of traffic was from the Bunge Flour Mills at Albury to the discharge point at Williamstown Pier. Another was from the Bridgewater Flour mill to Melbourne.
In the 1979 recoding, the class letters were altered to VPFX.
By the late 1990's, the vehicles were out of service.
In the mid 1990s, at least one flour wagon was converted for use as a loco sand transport, coded VPLX
There was one main design for the body, with two styles of piping for discharge gear. Early style had a set of three pipes and slots for the pipes to run. Hoppers built later featured a single pipe on one side. The early style were later modified to single pipe configuration.