With the transfer of operations from Rosedale to Mt Gambier, bogie exchange wagons were required. The QAB were unsuitable.
Six wagons were converted from SFX_ wagons in 1978. The numbers were 101 to 106.
The modifications to the SFX wagons included removal of chains and side stanchions. Webbing winches were fitted down one side and a lashing rail fitted to the length of the wagon down the other side, secured to the underframe.
In the 1979 recoding, the class was altered to VFMX.