About 1990, two VPFX wagons were converted for the transportation of locomotive traction sand. Until this time sand was transported by _HD_ sand trucks and some _J__ fixed wheel cement powder wagons placed into departmental traffic. The HD wagons were gravity discharge into a pit or buckets whilst the J wagons were air discharge into raised sand hoppers.
VPFX 4 became VZGX 4 and VPFX 17 became VZGX 17.