AEC Regent III RT

AEC Regent III RT
RT574 at Victoria on route 185 in 1974
Overview
Manufacturer	AEC
Body and chassis
Doors	1 door
Floor type	Step entrance
Powertrain
Engine	AEC
Dimensions
Length	26 feet (7.9 m)
Width	7.5 feet (2.3 m)
Height	4.4m
Chronology
Successor	AEC Routemaster

The AEC Regent III RT was one of the variants of the AEC Regent III. It was a double-decker bus produced jointly between AEC and London Transport. It was the standard red London bus during the 1950s and continued to outnumber the nowadays more famous Routemaster throughout the 1960s.

The prototype (London Transport RT 1) was built in 1938 with an AEC 8.8-litre engine (a stopgap measure until the new 9.6-litre was available) and air-operated pre-selective gearbox. Finding a satisfactory British substitute for the German air compressor, bought from Bosch, was to cause problems for AEC, once war broke out. A prototype chassis was placed into service, disguised as an old vehicle. It carried a secondhand open-staircase body previously carried on Leyland Titan (fleet number TD 111), dating from 1931. Thus bodied, RT 1 entered service in July 1938 as ST 1140, even though it was nothing like a standard ST vehicle. It continued in service until December 1938.

While the chassis was on trial, a new body was constructed at London Transport's Chiswick Works. Its four-bay body resembled that of the Roe Leeds City Pullman body exhibited at the 1937 Commercial Motor Show, though the overall impression of modern design and the features included marked a big step forward. This body replaced the old one on RT 1 and the bus re-entered service in 1939.

London Transport ordered 338 (later cut to 150) chassis which were in production when the war broke out, in September 1939. The last of the batch, RT 151, did not reach London Transport until January 1942, although all were built to pre-war specification. The only other RT-type chassis constructed before the end of the war was destined for, and went to Glasgow Corporation, originally intended to be an exhibit at the 1939 Commercial Motor Show, but cancelled due to the outbreak of war. It differed from the pre-war London examples in having a body built by Weymann (the front being very much in the Cowieson style), although the cab area/radiator was very similar to the London vehicles.