In the late 1970's, rail transport obtained contracts to move slab steel from Port Kembla to the BHP rolling plant at Hastings, south of Melbourne. Vehicles coded ESX_, later VODX were originally used. Later vehicles were bogie open wagons of the VOBX / VOCX type with doors removed were coded VOEX.
The VKOX class is numbered from 51 with numbers to the 80's. heritage not known. The number group follows the VKEX group of 1 - 50.
In NRC service the vehicle were reclassed to RKUX.