Class A1 Trolleybus Diddler
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Notes About This Vehicle

London United Tramways operated the first trolleybuses in passenger service in London from its Fulwell depot on 16th May 1931, replacing trams. The formation of London Transport in July 1933 brought the LUT under its control.
In due course trolleybuses became a familiar site in London, with the fleet reaching about 1800 at its peak in the early 1950s. Several batches were built during their heyday, each with alpha-numeric identity codes. In due course, the first two batches became known as ‘A1’ and ‘A2’ but were better known by the curious nickname of ‘Diddlers’, the origin of which is now lost to supposition.
The two batches were very similar, with chassis by AEC and powered by English Electric. The 56-seater bodies, by the Union Construction & Finance Co (UCC), were substantially of teak and ash construction and strongly resembled the ‘Feltham’ trams the vehicle they were to supersede.
The Diddlers ran in service until finally being withdrawn in September 1948 after which several were used as trainers.
Vehicle No.1, depicted in this drawing, unsurprisingly being the first, went through many design changes in its early years especially the front bonnet area. Other notable revisions affected the ‘indicators’ (jargon for the route number and destination displays).
With foresight, London Transport earmarked No.1 for preservation in 1949, long before the last trolleybuses of subsequent designs ran. It spent about a decade in store and then went on display at the transport collection in Clapham between March 1960 and May 1961.
Still in running order, it took place in the last day of London trolleybuses celebration on 8th May 1962 and went to Aldenham Works for much needed restoration in 1975. No.1 now resides at the London Transport Museum store at Acton.
The Museum chose to preserve Trolleybus no.1 in as near as possible to its condition when withdrawn from service. I have represented it here as best I can but have added a rear destination board of the general style used for most of its life, though the contents are educated guesswork.

Notes About This Drawing

The drawing is based on a Union Construction & Finance Co Ltd general arrangement drawing ‘223SA’ dated 10th July 1931. 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 over 200 colour photographs of the vehicle taken in April and May 2012 when under the custodianship of the London Transport Museum.
The drawing depicts the vehicle in its state of preservation at the time the photographs were taken and not necessarily at any particular time when in passenger 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.
For practical reasons the overhead wires are shown here lower than the normal operating height.
drawing copyright Douglas Rose June 2012
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