The story
The Forest of Dean has been exploited since ancient times, not merely for its timber, but also for the minerals beneath. All the ingredients for iron-making exist and have been used since the Roman period. The Industrial Revolution brought increased demand for coal and iron, but the Forest, while having both in abundance, was at a disadvantage, being isolated from its potential markets with only a few frequently impassable roads linking it to the outside world. The hilly terrain was unsuitable for the canals of the type which were being built elsewhere, but in the first decade of the nineteenth century plans were laid for a number of horse-drawn railways to carry goods cheaply to the Rivers Severn and Wye.
From Wikipedia’s article on Bullo Pill Railway, shared under CC BY-SA 4.0.3