Pwll-y-Llygod Bridge is a single arch bridge spanning the river Gwendraeth Fawr and dates from c1769, thus making it the oldest tramroad bridge in Wales and one of the oldest in the World. The bridge originally carried a tramroad running from Carway Colliery 1.5 km to the east, to the terminus of Kymer's Canal which lay adjacent to the bridge. Kymer's Canal (NPRN 34395) transported goods from a series of anthracite collieries and limestone quarries situated along the valley of the Gwendraeth Fawr, to a quay at Kidwelly. The canal became incorporated into the Kidwelly and Llanelli Canal and was later converted into the Bury Port and Gwendraeth Valley Railway. The tramroad and bridge then formed the Carway branch of this railway but was disused by the 1915 3rd edition Ordnance Survey. At this date a small section of railway up to and including the bridge survived as the Carway Siding.

The bridge is 3.3m wide and 24m long, it's arch 6.1m wide and some 3m high. It is constructed of course sandstone rubble with hammer-dressed sandstone voussoirs. Two buttresses against the west abutment of the south elevation, together with a small section of parapet are later additions presumably dating to the period of railway use. The northern elevation of the bridge has suffered damage and collapse as a result of vegetation growth, water scouring and flooding.

During a site visit in 1992 the remains of timber sleepers were visible on top of the bridge and both approaches, these were not visible during a survey of the bridge by the Royal Commission in April 2013.

Louise Barker, RCAHMW, June 2013.

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