Parsons' Railway - otherwise known as Parsons' Folly or the Glyncorrwg Mineral Railway - was built in 1839 to1842 to open up a vast area of previously inaccessible coal in the area behind Neath. It ran for 12.1 kilometres (7.5 miles) from the Neath Canal at Aberdulais to the small Blaencregan Level [SS 8555 9895]. The original owners were obliged to surrender possession in 1843 but regained it a few years later when their successors ran into difficulties. The whole project was unrealistic and the railway was lifted in 1852.

The tramroad ran from the Tennant Canal (NPRN 91664), at SS77429937, up a series of inclines to the north summit flank of Cefn Morfudd, then descended into Cwm Gwenffrwd, running along the Afon Pelenna valley before ascending towards Mynydd Canol and skirting the headwaters of the Nant Cregan, terminating at Blaencregan colliery/level, at SS85469880.

The line of the tramway is depicted on Ordnance Survey County series (Glamorgan. XVI.6, 10-12, 15; XVII.5,9 1877-82), where the north-west most circa 960m stretch, from SS78099877, is followed by a tramroad from Wenallt Colliery; the junction at the Tennant Canal appearing to have been obscured by the construction of the Vale of Neath Railway (NPRN 34885), opened in 1851.

The site comprises: Junction with Tennant Canal (NPRN 34839), Bridge & inclined plane on ascent to summit level (NPRN 309298; 34842)and Summit level (NPRN 34843). The summit level comprises: Embankment ( NPRN 309288), Cutting (Nprn309291), Bridge (NPRN 309293), Embankment (NPRN 309295). There is also a Winding House & incline descending from summit level (NPRN 309297; 34841) and Cwm Pelenna Bridge (NPRN 34844).

Stephen Hughes and Paul Reynolds (1989) 'A Guide to the Industrial Archaeology of the Swansea Region' Association for Industrial Archaeology.

David Leighton & John Wiles, RCAHMW, 8 November 2007 (edited by RCAHMW 14 October 2011)