Whilst the Archives at the Study Centre of the Historical Model Railway Society were being sorted out, a very faded drawing of a petrol locomotive was found. It is to 1½ inch = 1 ft scale and is titled "Arrangement of Works Petrol Locomotive". The locomotive carries the lettering "DENNIS BROS. LTD. GUILDFORD." The drawing has a label on it with the name Jym Leddy of Woking, presumably the gentleman who donated it to the HMRS. The drawing is much too faded to be copied, so I have redrawn it to 12mm =1ft scale, which fits conveniently onto a sheet of A3 paper. I cannot guarantee that every detail is correct, the arrangement and function of much of the works under the locomotive is not too clear. I have followed the layout of the original drawing but have amended the rear view to show the box body, whereas the original only shows this as dotted lines.
Reference to the Birmingham Locomotive Club's Industrial Locomotive Pocket Book C (South Eastern England, 1958) identified the locomotive as having been built in 1913. It ran until 1942, when it was replaced by a new Ruston diesel shunter. The brothers John and Raymond Dennis started a bicycle manufacturing business in Guildford in 1896. From bicycles, they developed through motor bikes and cars to commercial vehicles. In 1908, a new factory was set up at Woodbridge, to the North of Guildford between the Woking and Farnham lines of the London & South Western Railway. As the works grew, a siding from the Farnham line was put in.
Reference to "World Trucks No. 6 - Dennis" by Pat Kennett (PSL 1979) suggests that the locomotive is built from standard lorry components, having much in common with the "3-Ton subvention model", built from 1913 for commercial sale, but to a War Office specification and liable to be requisitioned.
The use of a sub frame to carry the engine and transmission was normal on Dennis lorries of the time, but is more apparent on the locomotive, as the main frame is mounted much higher than usual, to be at standard railway buffer height. The bonnet and cab are much as on the 3-Ton army lorry, but with a traction engine style canopy instead of the usual canvas hood. There is an open box body behind the cab, containing the petrol tank. This would probably also have been filled with scrap metal or other ballast material. The steel wheels are as on the lorries, but with U-section steel flanged tyres in place of the usual solid rubbers. The axle bearings are fixed to brackets on the main frame, with no flexible suspension at all.
The four cylinder engine is probably by White and Poppe of Coventry and the gearbox and worm driven rear axle are Dennis's own. The standard Dennis gearbox would have contained four forward and one reverse gear, it is not known whether the loco retained this capability. The plan view shows the location for a gear lever at the front of the box, but no gear lever is shown. The steering column is retained, to carry the hand operated throttle. There are clutch and brake pedals and a handbrake, to the right of the driver's seat. The clutch and handbrake both operate on the transmission line between the engine and the gearbox. The plan view shows that the footbrake is connected to a rod which heads towards the rear of the chassis, but it disappears under the petrol tank and does not reappear. There were, presumably, brake drums on the rear wheels. The side elevation shows a starting handle which apparently goes right through the front coupling. Presumably, the coupling had to be held to one side to start the engine.
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