In 1961 two cable wagons reclassed to SC. These were _E__ 125 to SC 125 and E 78 to SC 78. These wagons were for the transfer of power transmission cable for the Kiewa Hydro-electric scheme.
In 1965, two more wagons were placed into the class. SEF_ 26 became SC 26 and SEF 60 became SC 60.
In 1966 the SC wagons were modified for bogie exchange and reclassed to SCX. They were numbered 1 to 4 and were from SC 26, 60, 78 and 125 respectively.
In mid 1966 two more wagons were added to the class. SCX 4 and 5 were converted directly from E wagons.
In 1968 two more wagons were added. SCX 7 and 8 were converted from E wagons.
The SCX vehicles were used to transport drums of power transmission cable.
By 1979 most of the wagons had been converted to other wagon types. By this time they were only used irregularly.
In the 1979 recoding project, the SCX class was relettered to VFFX. Only wagons 3, 6, 7 and 8 were relettered.