RM 133 was shipped from Britain on 29 July 1956 and entered service on 26 November that year. It was based in Auckland for most of its life and occasionally ran in service coupled to RM 121. It was the last Drewry Railcar to run regularly schedualed services to Rotorua, New Plymouth and Taumarunui. RM 133 was withdrawn from service in May 1978 and in December that year was converted to an Ac Set (locomotive hauled carriage set) more commonly known as "Grass Grubs" due to their distinct green colour. Once converted, RM 133 was renumber Ac 13 (later Ac 8140).
After Ac 13 was withdrawn from service, it was sold to Auckland International Airport where it was used for staff evacuation training simulating an aircraft. In 2000 it was offered for preservation and was thought to be the only surviving example of a Drewry Twinset.
After suffering unfortunate fire damage to its No 2 end, the remains were removed in February 2002 from Auckland Airport and transported to the location of the Pahiatua Railcar Society in Pahiatua. The Lotteries Grants Board generously assisted the trust with a substantial grant to make this happen.
RM 133 is now in dry storage at the Pahiatua Railcar Society, with many of its components used for the restoration of RM 121.