When various NSW government owned assets were sold to private rail operators, some classes were split between government employ and private owners. The NSW Railways required private owners to renumber their locomotives to prevent confusion between private and government owned locomotives.Silverton bought a number of Mk1 48 Class locomotives from the NSW State Rail Authority, and renumbered them as "48s" class, along with their own DL531 units, and a pair of 830 Class purchased from Australian National.