In 1964 a new design flat wagon entered service. The wagon had a fixed bulkhead at one end and an adjustable bulkhead at the other. The wagons had deck and bulkheads similar to the QAB_ but were a shorter underframe, The code was SBX.
Four wagons were built in 1964 and nine wagons built in 1969. The numbers were 1 - 13.
The vehicles were used for panelboard transport.
In the 1979 recoding the wagons were relettered to VFJX.
They were all in storage by 1991/92 as there was no traffic for them, with some of the class scrapped during 1993.
They were used to transport packs of panelboard. The adjustable bulkhead at one end was used to secure the load.