“The Clydach Gorge – a natural route between Coalfield and Usk Valley - once possessed the highest concentration of tramroads in Wales.  The Clydach Railroad - an edge rail system permitted by the 1793 Canal Act - was first to connect upland coal and iron works with the Brecon & Abergavenny Canal at Gilwern.   Built by 1794 at least three years before canal construction began, the tramroad helped finance that project by transporting iron to Glangrwyne Forge and supplying the Usk Valley coal and lime trade, using lime from Black Rock Quarries and coal from the Canal Company’s Gelli Felen coal works, the latter via a tramroad link from  Pont Harri Isaac. Reaching Brecon by 1800 the canal made this town an important coal-trading centre with tramroad links into Radnor and Herefordshire.    Canal and feeder traffic increased greatly after 1812 when it was extended to Newport and the sea   At Gilwern the Clydach Railroad was provided with its own canal loading wharf, the original line to Glangrwyne passing under the waterway through an arched aqueduct.

The Clydach Railroad would transport heavy loads of Beaufort and Ebbw Vale cast iron and Black Rock limestone down the gorge carrying much Usk Valley timber and animal fodder for the return.  (Darren Ddu - Black Rock- Limestone quarries were connected by way of a tramroad spur.)    However heavy loading caused such edge-rail breakage it was soon converted into an L-shaped plateway.    Rails were cast at Merthyr’s Penydarren Iron Works and possibly Pen y Cae iron works, Ebbw Vale. Not many examples survive although one was used at the Drum and Monkey public house as a fire bar for many years, and another is fixed to a wall near Gilwern wharf.

The canal and its feeder tramroads – without which it could not have operated – would be killed commercially by steam railways.   By 1864 trade had fallen almost to nothing, the Clydach Railroad supplanted by the new Merthyr-Tredegar and Abergavenny Railway.    

Peter M. Jones /Eifion Lloyd Davies. 2015