 This, coupled with the demonstrated efficiency and economical operation of B class mainline diesel-electric locomotives introduced in 1952, made the high cost of installing storage and transport facilities for PBC uneconomic.The additional X class order had already been cancelled in favour of additional B class locomotives, and in January 1957 Victorian Railways announced the discontinuation of PBC operation and the intention to return X32 and R707 to black coal firing.X32, taken out of service in May 1956 pending repairs, was instead scrapped in August 1957.