The Rhymney Branch of the Barry Railway was opened in 1901 between Tynycaeau Junction on the main line and Penrhos Upper Junction on the Taff Vale Railway and in 1905 between Penrhos Lower Junction and Barry Junction on the Brecon and Merthyr Railway. Double tracked throughout, it passed, from south to north, through the 443m-long Garth Tunnel and over Walnut Tree Viaduct (nprn 34875), Pen-yr-heol Viaduct and Pwll-y-pant Viaduct and was the Barry Railway's link between the Rhymney Valley and Barry Docks.
The viaduct spanned the Taff Valley at Taff's Well and consisted of four brick arches and seven steel lattice girder spans supported on massive brick piers. Opened in 1901 and demolished in 1969, it stood 36.6m high and was 472m long. Two brick piers remain; one on the east bank of the River Taff (at ST 12608 82880) stands as a monument to the Silver then Golden Jubilee of Queen Elizabeth II.
B.A.Malaws, RCAHMW, 29 June 2009.