WD 'Standard' 0-4-0
Diesel Mechanical Locomotives
1941 - 2008
General history of the smaller Army diesels
The standard army 0-4-0 diesel mechanical locomotive design traces its development back to the very beginning of the diesel era in Great Britain, broadly similar machines being produced by various manufacturers as early as 1934 (the earliest Army machine originally being built for the LMS). Early versions of these machines differed considerably in detail but the basic design adopted by both Andrew Barclay and Vulcan Foundry remained unchanged from the mid 1930s until the general end of mechanical transmission locomotive production in the 1960s. Note that all the Vulcan machines were ordered through the Drewry Car Company who did not actually build locomotives and the Army tended to call all of them Standards or Barclay/Drewrys. The basic design consisted of a 6 or 8 cylinder Gardener engine (other makes were tried early on) driving a 4 speed (earlier 3, later 5) epicyclic gearbox through a fluid coupling avoiding the need for a clutch. Earlier Vulcan locomotives used English Electric - Dick Kerr frames and did not carry Vulcan works numbers - see the excellent Vulcan foundry history site for copies of the original works lists etc.
One of the early locomotives (Barclay 331 of 1938) from a 1952 Barclay catalogue
Locomotives built up to 1938 were effectively prototypes with considerable differences and later machines were built in two distinct phases, one in 1940-42 and the remainder in 1945. However very similar locomotives were also built for royal ordinance factories and, at least on Barclay works lists, were ordered before the 1940-42 batch but some were delivered later. It is assumed that at least part of the reason for the 1941 batch was to replace requisitioned locomotives (mainly LMS 0-6-0 diesel electrics) lost in the fall of France. The 1945 batch were obviously constructed with the invasion and later rehabilitation of the damaged railways of the rest of the world in mind but were delivered too late to be of use (three of those ordered from Drewry were cancelled). Many of the first series were used abroad with some remaining to be adopted into the stock of various national railways. Apart from detail differences between manufacturers and in the type of final drives fitted which apply to both early and late types the batches also differed from each other in that the early types had semi-open cabs following steam practice and solid bonnet doors, while later types had full cabs, louvered doors and detailed differences in handrails etc. Pre and post-war locomotives had conventional combined coupling and connecting rods with split bushes driving the rear wheels but both production series used long connecting rods from the jack shaft driving on the front wheels with separate connecting rods, presumably to reduce the skill required in manufacture. As yet the author has not been able to determine which design the later Barclay ROF locomotives had. All the production machines had (air start) 154Hp Gardener 6L3 engines, 4-speed Self Changing Gears transmission, air brakes and electric lighting, combining with the flameproof exhausts to allow use within ordinance factories and ammunition dumps. No further machines of this type were built for the Army but the basic design was sold to industry by both Barclay and Vulcan/Drewry and formed the basis of BR class 01 and (with 8-cylinder engine) class 06 while an 0-6-0 version became BR classes 03 and 04.
One of the later locomotives (Drewry 2205/Vulcan 5267) as rebuilt by Baguley in 1952 from a 1960 Army spares list
In later years the early series machines had the cabs fully enclosed and most of the long term survivors were fitted with extra lights, warning beacons and electric start. Some locomotives were rebuilt with later final drives, while others were derated to 100Hp probably to prevent transmission damage. A number of the machines (most of the later batch in fact) received more comprehensive rebuilds in the late 60s /early 70s when more modern Gardener engines of type 6L3B rated at 196Hp were fitted. It is fair to say that the rebuilds were not particularly successful as the original transmission struggled to transmit the extra power while the 0-4-0 wheel arrangement and 10-ton axle loading could not easily impart it to the train! For more details and photographs of the earlier locomotives see the excellent web pages of the group who are restoring WD33 as well as my summary tables (see below).
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Copyright R. Hingley (2002-2010)