By the end of the Great War, both the Allies and the Central Powers were using narrow gauge railways to supply troops in the trenches and other forward positions. However, the British Army had been slow to adopt the concept, putting their faith in motor lorries and horses to move supplies from the standard gauge railhead. When the War Department Light Railway (WDLR) was eventually established in 1916, it was well resourced and developed quickly to meet a range of logistical needs.
An initial order of 1,000 miles of 60 cm gauge track was placed, along with orders for large numbers of steam and petrol locomotives. The WDLR also sourced 1,000 four-wheel wagons with steel frames and 3-plank wooden bodies. In the light of experience in the field, the specification was amended to in include, among other improvements, removable sides and ends. These wagons were lightweight so that they could be taken forward by locomotives as far as was safe and then hand-worked into position by the troops on temporary trench tramways. It was soon realised that wagons with greater capacity were required for efficient locomotive working and, consequently, a larger version of the four-wheel wagon was introduced. In true military fashion the WDLR wagon types acquired letter designations, these first two being, not surprisingly, Class A wagons and Class B wagons. Demands for supplies, particularly shells for the artillery, continued to increase and a Class C wagon was specified and ordered. Class C were wooden-bodied bogie wagons with twice the load capacity of a single Class A wagon. In the light of ever increasing demand for supplies, the decision was made to use heaver rail on the WDLR to allow greater axle loading and a larger Class D bogie wagon was designed that became the mainstay of future British narrow gauge traffic on the Western Front. Class D wagons were steel-framed, wooden-bodied open wagons that permitted a wide range of loads, or troops, to be carried. The War Department drew up a detailed specification for each class of wagon, which allowed different companies to contribute to the war effort. Although all Class D wagons were of the same dimensions, they came with a three or four plank body dependant on the manufacturer.Class E wagons were the same as Class D wagons but with a dropped centre between the bogies. This was designed to allow the transport of bulkier, but lighter, supplies such as animal fodder. Class F wagons were a derivative of Class E wagons with no bodywork above the solebars. In place of the upper bodywork were eighteen removable stanchions that permitted large, heavy items, such as field guns, to be carried. All these classes of WDLR wagon were built with versatility in mind but a number of operational requirements led to the development of specialised rolling stock.Paraffin, cylinder oil and lubricating oil were required for servicing the large number of petrol locomotives. Consequently, Class G wagons had three rectangular tanks mounted on a four-wheel Class A frame. These wagons were not produced in large numbers, unlike the next class of wagon. Clean water, for the troops and the steam locomotives, was in constant demand and so the Class H wagon was a 1,500 gallon capacity steel tank mounted Class D frame and standard WDLR bogies. The following letters, I and J, were not used in the wagon classification system.Class K wagons were side-tipping skips bought from the catalogue of Hudson (18 cu ft capacity) or McLachlan (27 cu ft capacity). Very large numbers of these wagons were used for all types of construction work, including permanent way work. Assembled into rakes using chain couplings, Class K wagons did not posses the standard WDLR coupling. Class L wagons were ordered from the USA when domestic production of skip wagons could not meet the demand. These wagons were wooden-bodied side-tipping wagons, similar to the MSC contractor wagons in the UK.Class M wagons were something of an anomaly, as the M was for monorail, with the wagon intended for man-hauled use on one rail of a trench tramway. A very small number of side-discharge ballast hopper wagons, classified as Class N wagons, were obtained from Hudsons. These appear to be the standard permanent way wagon already produced by that firm. Letter O was not used for wagon classification, probably because it was one of the three letters in this part of the alphabet that could be easily mis-read as numbers.The final wagon in the WDLR classification, Class P, brings us full circle in the development of rolling stock in a surprisingly short period of time. Class A wagons had been built light enough to be moved forward by troops on the trench tramways but, as we have seen, they were soon superseded by larger and heavier wagons that were needed for efficient locomotive haulage. By 1917, a number of ration wagons were being built specifically for troop-haulage on trench tramways as the other classes of wagon were too heavy for the track of the trench tramways, and the available manpower.Although the ration wagons were of a variety of designs, from a number of manufacturers, they became classified as Class P wagons. Rather than the detailed War Department specification of the other WDLR classes, Class P wagons were only required to be light enough for man, or animal traction, but strong enough for haulage behind a 40 hp petrol locomotive. This was to obviate the need for transhipment from the larger wagons and is pretty much where we started with the small Class A four-wheel wagon. Having scratch-built and kit-built examples of ten of the WDLR wagons classes, there remained only the N and P to complete the set. The Class N wagon was made on a simple wooden frame with plastic bearings, for the IP Engineering 16 mm diameter wheelsets, mounted in the solebars. Plasticard was used to fabricate the body with a load of poor quality ballast that was typical of the Western Front. Roy Plum had designed a 3d printed a 7/8ths scale Class P wagon, and I was grateful that he produced a 16mm version for me. This completes the WDLR wagon classes but there are numerous other wagons to build next that were not given a class designation.
1-WDLR wagons for lighter track (left to right): a scratch built Class A wagon, a Red Star Class C wagon and a 3d printed Class B
2-WDLR wagons for heavier track (front to rear): a Red Star Class F wagon modified as a field gun carrier, a Swift 16 Class D wagon and a Red Star Class E wagon
3-Specialised WDLR wagons (anticlockwise from rear): a Swift 16 Class H water tank wagon, a Red Star Class G wagon and a Binnie Class K wagon
4-Making a start on the WDLR Class N wagon.
5-WDLR Class N side-discharge ballast hopper wagon.
6-3d printed WDLR Class P ration wagon having sustained some light battle damage.
July 2020
