Bailey's Tramroad Bridge is a fine round-arched stone bridge with a high curved causeway on the western approach. It was built in 1821 to carry the 4ft2in route from Nant-y-Glo Ironworks to Govilon canal wharf.
The tramroad which approaches the bridge, for about 100 metres each side, is terraced into the valley sides and is wide enough for double track, whereas the bridge itself is of single track width.
At a site visit by B.A. Malaws on 21 September 1999 the bridge was noted as being heavily overgrown.
Claire Parry, RCAHMW, 21 July 2011.
A Guide to the Industrial Archaeology of South East Wales, AIA, 2003