The Scammell Scarab is a British 3-wheeled tractor unit produced by the truck manufacturer Scammell between 1948 and 1967. Its name is commonly believed to be derived from the rounded bonnet that resembled the elytra (wing covers) of a Scarab beetle, but the name really comes from a more conventional source, Scammell's idea of the combination of an Arab horse (which the Mechanical Horse replaced in BR usage) and the word Scammell. Sca-rab = Scarab. The official Scammell Lorries LTD advertisement film makes reference to this. It was extremely popular with British Railways and other companies who made deliveries within built-up areas. The Ministry of Defence also used the Scarab and trailers for predominantly internal transport on large military bases.
Development & Production History
The Scammell Scarab was the successor to the Scammell Mechanical Horse and production began in 1948.
In the late 1920s the railway companies were looking for a suitable vehicle to use on their town parcels delivery traffic, which was predominately horse drawn. The London Midland & Scottish Railway experimented with various ideas and in late 1930 announced, jointly with Karrier Motors, a tractor unit for this purpose. The vehicle, the Karrier Cob, was powered by a twin cylinder Jowett engine and utilized a mechanism to couple existing horse trailers to the tractor unit. Meanwhile the London and North Eastern Railway had approached Napier's, the quality car and aero-engine makers for an answer to the same problem. They came up with some ideas, but did not wish to develop the concept and sold the project to Scammell Lorries of Watford. Their designer, O. D. North refined and further developed the concept of the three wheel tractor unit which automatically coupled and un-coupled trailers and in 1934 announced the introduction of the Mechanical Horse.
The Scammell Mechanical Horse, with its very 'square' wooden cab and steel chassis, remained largely unchanged until the late 1940s when the tractor section was redesigned creating the Scammell Scarab. This featured the same successful automatic coupling from the original but now used the Scammell 2,090cc side-valve engine in both the 3 ton and 6 ton versions. A diesel version was also introduced with a Perkins engine. The Scarab's cab was more rounded and made from steel and with the engine being mounted lower and more central than in the Mechanical Horse the Scarab was much more stable. The railways for which this style of vehicle was originally designed continued to be a primary customer, although there were many other users, the maneuverability proving popular for companies operating in city environments.
Production of the Scarab ceased in 1967 and was replaced with the Scammell Townsman that now featured a fibreglass cab. The Townsman utilized many developments in large vehicles including vacuum-assisted hydraulic brakes and although the same automatic coupling feature was used this now used a vacuum operated release mechanism rather than a hand lever found in earlier models. Despite numerous improvements the Townsman was mainly only sold to British Rail and the Royal Mail and production ended in 1968. The Scammell or "FAR" was also made under licence by the French company Chenard-Walker and used the Citroën Traction Avant engine. Production of this version began in 1937, and was known is France as the Pony Mécanique. This continued in production, in various versions, until 1970.
A four wheel version of the Scarab was produced, although problems with the cooling system meant only around 200 were produced, the majority of which were exported to South Africa
Scammell Lorries produced approximately 30,000 Mechanical Horses of all types; of these, about 30 original Mechanical Horses, 60 Scarabs, and 30 Townsman are known to survive together with 3 Karrier Cobs and two Jen Tugs. Examples may be seen at a number of museums and Heritage Railways. The Mechanical Horse Club regularly have a display stand and preserved vehicles within the Commercial Vehicles section at the annual Great Dorset Steam Fair.
The restoration of a Scarab to working order was the subject of a programme in the third series of Salvage Squad. The final filming session took place at "The Vintage Carriage Trust" at Ingrow Station, on the Keighley and Worth Valley Railway in West Yorkshire, on 22 November 2003, where it was handed back to its owner,Chris Waye, out-shopped in the standard British Railways road vehicle livery of carmine and cream.