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Glan Rhyd Bridge
Ogmore River, Pen y Fai, north of Bridgend, Wales, UK
Glan Rhyd Bridge
associated engineer
John Hodgskinson
date  1829
era  Georgian  |  category  Bridge  |  reference  SS898828
ICE reference number  HEW 1084
photo  © Martin Edwards and licensed for reuse under this Creative Commons Licence
Glan Rhyd Bridge was was originally built as a tramroad bridge. Constructed in masonry, it now carries a minor road across the Ogmore River between Pen y Fai and Sarn, to the north of Bridgend in South Wales. It sits below the M4 motorway's Ogmore Valley Viaduct, for which it was used as part of the formwork support during construction. The proximity of the two structures neatly demonstrates the changing scale of transport provision since the 19th century.
The bridge, also known as Tyn y Garn Bridge or Glan Rhyd Railway Viaduct, was constructed as part of the Bridgend Railway, a 7km horse-drawn tramway that ran eastwards from near Cefn Cribwr to cross the Ogmore River and turned southwards along the east bank of the river to Bridgend. The railway was an eastern branch of the 27km Dyffryn Llynfi Tramroad, which linked the Dyffryn collieries and various ironworks in the vicinity of Maesteg with the small harbour at Porthcawl.
The tramroad, also known as the Dyffryn Llynfi & Porthcawl Railway, was completed in 1828 and Bridgend Railway in 1830. John Hodgkinson (1773-1861) of Newport was the engineer for both schemes, and both were constructed at a gauge of 1.397m (4ft 7in).
Glan Rhyd Bridge is of coursed and squared rubble masonry (limestone or sandstone), well proportioned with a high standard of detailing. It is 44.7m long overall and about 4m wide between parapets. Its three rounded segmental arches span 7m, 9.4m and 7.9m, with a maximum arch rise of 3m. The arch spandrels feature single voussoir rings and projecting keystones. The two river piers include substantial stepped cutwaters on both sides, which are triangular in plan.
A carved stone plaque in the centre of the inner face of the upstream (north) parapet wall reads, "THIS BRIDGE WAS ERECTED IN THE YEAR 1829 BY MORGAN THOMAS LALESTON MASON".
The Bridgend and Dyffryn Llynfi & Porthcawl Railways were taken over by the Llynvi Valley Railway. From 1861, steam locomotives rather than horses worked the lines, though locomotives never used Glan Rhyd Bridge itself. Between 1864 and 1867, it ceased to be part of the tramroadís route, parts of which had been abandoned.
After the tramroad closed, the bridge was adapted for road traffic and the rails removed. While the 373m long Ogmore Viaduct on the M4 motorway was being constructed in 1978-81, the bridge was used as a support for a short section of centring for the new structure. It now sits in the viaductís shadow.
Glan Rhyd Bridge was listed in July 1963 and now has Grade II* status as "a rare and especially fine example of an early railway bridge and an important component of the early industrial history of the district". Commemorative plaques have been erected to mark the tramroad termini at Maesteg, Bridgend and Porthcawl.
Contractor: Morgan Thomas of Leleston
Research: ECPK
reference sources   CEH WalesBDCE1

Glan Rhyd Bridge