Devizes is a town in central Wiltshire. Now most famous for Caen Hill locks on the Kennet and Avon Canal, it was formerly served by a Great Western Railway line, which passed through a tunnel under the castle to the east of the station. Initially the terminus of a branch line which began at Holt Junction on the Wilts, Somerset, and Weymouth Railway, Devizes later became a stop on the through route from Paddington to Weymouth when the Berks and Hants Extension Railway was built to link the branch with an existing line from Reading to Hungerford. In 1900, the Stert and Westbury Railway was opened, bypassing Devizes, which was now on a less important single track line from Patney and Chirton to Holt Junction.

The layout represents the goods yard to the northeast of Devizes station in the late 1930s. The main objective was to create a layout where there were plenty of interesting possibilities for shunting, but which also allowed a wide variety of trains to be run on the main line to provide a more relaxed option. The line from Holt Junction (the curve on the left) splits into three. The northernmost is the Up platform, the middle the Down, and the southernmost is bi-directional (I may swap the latter two if experienc shows that this makes the layout nicer to operate). In the Fiddle Yard, the plan is to use the uppermost through line as the running line, with the rest as storage sidings.

In 1938, a bridge elsewhere on the line was upgraded, and Red engines were now permitted to run via Devizes. Local freight services (worked from Holt Junction and Westbury) often used 57xx locomotives from Westbury. Local passenger services were autotrains, likely hauled by 5400 class panniers. Longer distance freight trains were hauled by moguls, and long-distance passenger services seem to have moved over from Manors to Halls, Saints, Stars, and Castles during this period.