Railway Viaduct over Nant Clydach (partly in Abercynon Community)

The Railway Viaduct over Nant Clydach is a three-bay structure built in two phases. The wider section on the west side was constructed between 1837 and 1841, while the narrower section on the east side was completed from 1861 to 1862. Both sections are made of coursed rock-faced stone. In the center, there is a wide elliptical arch that spans the river, supported by projecting impost bands, with the inner sides of the piers now reinforced with concrete. The narrower, round-headed outer arches cross unclassified roads. The parapet features replaced steel railings set on original hammer-dressed coping stones. Stone retaining walls are built against the outer arch abutments, except on the southeast side, which has an earthen bank.