RTL139 was delivered to new Chiswick works at the end of February 1949 and commenced service from Riverside garage a few days later. After three overhauls, and a period of time on the works float system, the bus was finally withdrawn in 1967.

Upon withdrawal, it was sold to Louwman & Parqui of Leidschendam, who exported the vehicle to The Netherlands for display at the HET National Automobielmuseum near The Hague to complement an earlier exhibit, STL441.

The Dutch Motor Museum closed in 1996 and the RTL was purchased by a Trust member and donated to the Museum, arriving at Cobham in October 1998.

The vehicle is very original, having been sold directly from service to a museum, who ensured the condition did not deteriorate. Some work had been carried out on the bus at Cobham. This has included relaying the cork tiles on the floors, cleaning the seats, and recently repainting the roof where the paint had faded.

The bus has been used in service in London on several occasions since its repatriation, and is sometimes used on the Museums route 462, on open days.