Roof Box STL  Central Area
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Notes About This Vehicle

Before the RT started to dominate London Transport’s double-deck fleet after the Second World War, many other classes of vehicle had been through the usual inception, design evolution and eventual demise.

The STLs were the last new type of double-decker introduced by the London General Omnibus Company before being absorbed into London Transport in 1933. They were also the first to take advantage of 1932 legislation for 2-axle vehicles, allowing an increased length from 25 to 26 feet, and an increased gross weight from 9 to 10 tons.

At this time the Metropolitan Police had many powers over the construction and use of public service vehicles in London and it took a couple of decades before such things as an upper deck roof, a roofed and eventually enclosed driver’s cab, and an enclosed staircase, became the norm. It could be argued that the STLs were among the earliest to have a properly thought-through design embracing all of these features from the start – though there was still no cab door.

STLs existed in many forms, with body variations classified up to 20, of nearly 2700 built, though all had the same basic design of chassis. Some of the earlier vehicles sat appreciably higher at the front, owing to suspension changes made when diesel engines replaced those fuelled with petrol. From STL2516 different radiators were fitted, though in other respects the front ends were very similar, with all bodies basically the same length, width and height.

An interesting feature on STLs was the rear upper deck emergency window. To open these, the triangular glass had to be pushed out from the inside to reach the handle. An earlier design appeared on LTs and STs and had an internal handle behind a pane of glass. A modified ‘Y’ type mechanism was first fitted to the ‘Bluebird’ LTs and STs and then on the STLs and finally the STDs, which came later on during the STL production period.

Front roof route number boxes were a later addition on STLs, making their first appearance on the STL12 and STL14 bodies. The roof boxes were a feature destined to continue on the next generation RTs.

With a total of 360 built by London Transport at its Chiswick Works within ten months, the roof box STLs commenced service in October 1936, largely replacing the remaining NS class. Existing legal agreements precluded them building all the bodies required themselves and an order for a further 175 was placed with Park Royal Vehicles – these becoming STL15s. A further 327 followed from Chiswick, all of the STL12 and STL14 type, and finally the STL16s, of which there were 132, distinguished by a new and deeper radiator, and also with wheel hub covers front and rear.

Built in November 1937, STL2377 is from the batch of 327 Chiswick-built bodies and was withdrawn in 1953. It survives in a heavily restored state, largely as depicted here, in late pre-war condition.

Notes About This Drawing

The drawing is based on Chiswick Works general arrangement drawing 3659 of STL body style 16 and dated 30th March 1939. 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.

I have inferred as much detail as can from published contemporary black & white photographs, of which there are few, and most of the livery from the body style 14 restored bus as it was in August 2019.

The colours of the adverts are also based on how they were on the bus in 2019; I have no idea if they are right. However, I have drawn them, I hope, more to the correct dimensions and also lettering styles of the period.

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 April 2020
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