The trolleybuses for London were designed and built specifically to be worthy tram replacements. Like the trams, they were large high-capacity double deckers, with rapid acceleration. All but one had three axles (necessary for licensing at the time as they were 30 feet long), and were much quieter in operation than contemporary trams or diesel buses. Trolleybuses were built on AEC, Leyland and British United Traction chassis.
Apart from the Diddlers and a few experimental vehicles, most London trolleybuses were near-identical. There was an exception: in 1941 and 1943 London Transport acquired 43 trolleybuses that had been ordered for South Africa but could not be shipped there because of the war.] These vehicles were allocated to Ilford depot. They formed three different classes and needed special dispensation because they were eight feet wide, six inches more than the law allowed.
Some later pre-war vehicles made use of modern monocoque construction techniques to produce chassisless bodies, where the mechanical and electrical parts, including the traction motors, are affixed to the bodywork and not to a separate chassis.
One experimental vehicle was proposed to be the forerunner of a fleet that would use the Kingsway tramway subway, but the change of policy after the war meant that this was never carried out.
The Q1 class were the only trolleybuses built for London after the War. A handful of pre-war vehicles were sold for further use in Panang (Malaysia), while most of the post-war ones, including the Museums 1348 were exported to Spain where they worked for various operators - some into the 1970s.
Some London trolleybuses are now preserved in the United Kingdom by the East Anglia Transport Museum, the London Transport Museum, and at The Trolleybus Museum at Sandtoft which is where 1348 resides. It was one of the 1948 vehicles that went to Spain. It was repatriated some years ago, and then extensively restored to return it to its London layout and condition.
This vehicle is in ticket and runs regularly at the Museum.