In the 1979 recoding the tank wagon group was split into various groups depending upon product carried.
Tank wagons used for the transport of bitumen were coded VTBA, VTBY, VTBX. The VTBY class was relettered to VTBF later.
One group of the Mobil bitumen tankers were named. The ends were painted with R.T.C. ( Rail Tank Car ) and the names were from prominent people within the history of the petroleum industy. RTC Macadam was one such vehicle.