Class A1 Trolleybus Diddler
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Notes About This Vehicle

London’s famous Routemaster was first shown in its prototype form as RM1 at the Earls Court Motor Show in 1954. After extensive testing, along with three further prototypes, the first production Routemasters entered passenger service in 1959.
Legislation of the time allowed buses of 8ft width but restricted the overall length to 27ft 6ins. When the regulations altered to permit buses of 30ft length, the opportunity was taken to extend the Routemaster.
The chassis-less construction of the basic Routemaster design made this relatively easy to achieve by moving the front and rear sub-frames farther apart and adding a further window bay near the centre. This allowed the standard 64-seat capacity to be increased to 72, by adding four seats to both decks.
Though the central square window looked what it was, an after-thought, it was nevertheless incorporated without spoiling the overall elegance of the bus’s appearance too much. A further consequence was the necessary introduction of an emergency exit window to the offside lower deck.
Two of the four prototypes had identity changes during their lives, though the standard Routemasters in service carried the fleet designation of ‘RM’ from the outset. They were numbered RM5 upwards, by now reaching RM879. Though it was initially intended the 30ft buses would carry the fleet numbers prefixed with ‘ER’, for Extended Routemaster (and indeed the first four had such transfers applied) they all came into service as ‘RML’, for RouteMaster Lengthened.
The first batch of 24 extended vehicles was thus delivered with the identities in this RML series, with fleet numbers from 880 to 903. Though not all entered service straight away, these buses were delivered to Finchley garage (code ‘FY’) to operate as part of the trolleybus replacement programme, with route 104 superseding the 609.
The bus in this realization is RML885, which was used for official LT photographs. All the others were to the same design, with a couple of minor style changes. From RML886 and upwards, the central vertical divider of the radiator was polished to match the rest of its surround; from RML901 upwards, the used tickets box seen to the left of the platform entrance was painted black. Other minor details changed too, lost in the mists of time.
Later RMLs, carrying fleet numbers 2261 to 2760, had further small detail differences, principally on the front wings and radiator grille.

Notes About This Drawing

The drawing is based on a Chiswick Works general arrangement drawing from 1961, (‘ER001.Z.’) revised a few times to 1965. This type of black & white sketch drawing, as implied by the name, is not intended to define detail but as a specification guide to builders.
All the fine detail has been interpreted from several black & white and colour photographs of sufficient quality that could be found and attempts to show the vehicle as closely as possible to how it looked when it entered service. None of the detail can be regarded as definitive.
It should be understood that all four elevations are seen here as one would see each part of the vehicle at a truly perpendicular angle. In real life this is of course impossible.
drawing copyright Douglas Rose March 2018
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