A tunnel on the Dowlais Iron Company's railway (SO09520584-SO09490582): Ordnance Survey six-inch Second Edition1(901).

The tunnel formed part of a mineral railway which linked Fochriw Colliery to the GWR and Rhymney Joint Line at Cwm Bargoed. It was built by the Dowlais Iron Company and is labelled 'Tunnel' on the 1884 OS map. The tunnel has been destroyed by infilling and regrading, the east portal no longer extant, but a cutting is still visible at the west end.
Recorded as part of RCAHMW Uplands Initiative Project, W B Horton, H & H, 17/09/2013.