The Neath River Swing Bridge was originally part of the Rhondda and Swansea Bay Railway and it was constructed between 1892 and 1894. Much of the route is now closed, but the section incorporating the Neath crossing now forms part of a goods traffic route. The bridge's total length is 118 metres of which the opening span is 55 metres long. There are three steel approach spans on the west side and two on the east.

The spans have a plate girder and are supported on piers each of which consists of a pair of cylindrical columns, either of wrought iron or steel plate, which are connected by horizontal and cross bracing. The opening span is pivoted centrally on a pier consisting of six cylindrical columns, similar to those which form the piers to the approach spans, but placed in a ring. They are capped by a large cylindrical drum containing the supporting rails and the operating mechanism. The swinging span 8.2 metres wide.

Source:
Stephen Hughes and Paul Reynolds (1989) 'A Guide to the Industrial Archaeology of the Swansea Region' Association for Industrial Archaeology & NMRW notes by Stephen Hughes.

RCAHMW, 20 October 2011.