The Loughor Viaduct is the only surviving timber viaduct that was designed by I.K. Brunel and L.E. Fletcher. It carries the South Wales main line across the tidal estuary of the River Loughor. The viaduct was constructed in 1852, it has eighteen spans each of about 12 metres (40 feet). The structure was originally built entirely of timber, although it has since been re-decked successively by wrought-iron and then steel plate girders. An opening span of swing-bridge type at the western end was replaced by a fixed span during the nineteenth century. Parts of the substructure are original.

Sources:
Institution of Civil Engineers B7 files, HEW1131, O.M. Gibbs, assisted by Stephen K. Jones.
Site entry by Stephen Hughes for Buildings of Glamorgan, John Newman, 1995
Stephen Hughes and Paul Reynolds (1989) 'A Guide to the Industrial Archaeology of the Swansea Region' Association for Industrial Archaeology.

RCAHMW, 19 October 2011.