as Open, plus armoured side doors and visors Armoured: completely enclosed with armour-plated roof, and end slits for the driver to look through The Dorman engine used by Motor Rail from the earliest days was reported in 1918 to have been "designed by Mr Abbott, in conjunction with W.H. Dorman Ltd of Stafford", which could explain why the company exclusively used this engine. The same article states that the WW1 production of the Dixon-Abbott gearbox was contracted out to David Brown Ltd. of Huddersfield. With over 900 such locomotives supplied to the WD and MoM, post-WW1 the resultant large and cheap supply of these trench tractors opened up the use of internal combustion engine powered locomotives to many new and existing applications, where steam engines were either too heavy or too expensive thus allowing cheaper operations. The company had found its niche, and continued to build petrol and diesel-engined locomotives, mainly for narrow gauge railways. In 1931, the company changed its name from Motor Rail & Tram Car Co to Motor Rail Ltd. The trade name Simplex was registered in 1953, though the name Simplex was in use by the company as early as 1915. In 1972 the company was renamed Simplex Mechanical Handling Ltd. Locomotives Other products In the early stage of its development, the Motor Rail & Tram Car Company was involved in developing self-propelled tramcars, though the extent of production is not clear. In 1915, The Engineer magazine reported on the Simplex Rail Coach made in Lewes with the Brush Company building the body, delivered to the South Indian Railway Company where it was expected to be run on the Pamban Viaduct line. The coach weighed 12 tons, would carry 70 people, and was powered by a four-cylinder Dorman petrol engine rated at 45 bhp. The tram car part of the company name was dropped in 1931, so it is presumed there was no tram car part of the business beyond this date. In 1919, Motor Rail manufactured some standard gauge inspection cars for the Ministry of Munitions, and the testing of these cars on the branch line between Bedford and Hitchin was reported in The Engineer. The cars were powered by the two cylinder Dorman engine with Dixon-Abbott 2-speed gearbox, and averaged over 30 mph on the test, and reached 43 mph. One of the cars was run on paraffin, though it was intended they would