When the GWR extended the Leominster to Kington branch on to New Radnor, the new railway ran for a distance parallel to the old horse drawn tramway which ran up on to Hergest Ridge. The tramway was upgraded to a steam powered narrow gauge line initially using a variety of locomotives but subsequently was able to make use of the ex- Glyn Valley Tramway locos which were purchased from the official receiver in 1935 and re-gauged to 2ft 3in.

The GWR were persuaded to construct a small station at Hergest to allow a secondary interchange between the standard and narrow gauges. As well as servicing facilities at Hergest, the narrow gauge railway provided the local community with a means of transporting incoming coal and outgoing stone and local foodstuffs.

The layout is set in the autumn of 1947, a surfeit of ex- army road vehicles and the return to civilian life of men seeking work would lead to the closure of both the narrow gauge and standard gauge railways within the next five years.

A full history of the line is displayed on the layout