RLH stands for «Regent Low Height»; being 13 feet 4 inches, this height enables the type to pass under lower railway bridges than normal double decker buses, which are around one foot higher. The reduction was achieved by creating a sunken upstairs gangway along the offside, and having rows of 4 seats together. This method of design was not new, for a fleet of 50 previous «lowbridge» bus types existed in London in 1952.
The first batch of 20 RLHs were originally intended for Midland General as part of an order for 30 low bridge provincial buses. Only 10 were actually required and the remaining 20 were offered to London Transport who bought these instead, and then a new order for the second batch of 56 slightly different vehicles two years later. These were used to replace 42 low bridge STL type buses dating from 1934 and 1942-45, and 8 low bridge ST Regents dating from 1930.
The RLHs were composed of a provincial style Weymann body (built in Addlestone, Surrey), mounted on an AEC chassis (built at Southall, Middlesex). See the Technical Specification page for more details.
Fifty of the 76 RLHs were painted green and used in the Country Area of London Transport, and some to its successor London Country. The remaining twenty-six were painted red for use in the Central Area of London Transport. See the London Transport Operations page for more details of routes and garages during this period.
The RLH was unusual for a London Transport bus because when overhauled, the bodies were always reunited with their original chassis each time. The much more common RF and RT vehicles of the same age would almost always have a different chassis fitted to the body at each overhaul (because it was more efficient for the process). The RLHs all received three overhauls, spaced around every 4 years, except for twelve RLHs which only received two (RLHs 13, 37 to 43, 48, 51, 75 and 76).
The last RLH to run in London Transport service was in April 1971 in Dalston. But for the majority of the class, this was only the end of one chapter in their existence- for many were to go on to 'second lives'.