Bridging the gap

One of the most striking structures in Merthyr if Cefn Viaduct. You can’t miss it, but how much do you know about it?

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Cefn Viaduct photo courtesy of Christopher Surridge

The viaduct was commissioned by the Brecon and Merthyr Railway company to span the Taf Fawr Valley in Cefn-Coed-y-Cymmer. Before work began, a special Act of Parliament had to be sought in 1862 to allow construction. The viaduct was designed by Alexander Sutherland and Henry Conybeare, and was built by Thomas Savin and John Ward. In early 1866, the project faced disaster when Savin and Ward suffered serious financial and legal difficulties. It was eventually completed with the assistance of Alexander Sutherland, and was completed on 29 October 1866 at a cost of £25,000.

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Cefn Viaduct under construction courtesy of Old Merthyr Tydfil (http://www.alangeorge.co.uk/index.htm)

The viaduct is 770 ft long, and at its highest point stands 115 ft high; it has 15 arches, each one 39 ft 6 inches wide. It was planned to be constructed entirely of limestone , but a strike by stonemasons in February 1866 caused the company to buy 800,000 bricks and use bricklayers to complete the 15 arches. The most striking feature of the viaduct is its elegant curve. The viaduct was apparently designed this way to avoid encroaching on Robert Thompson Crawshay’s land.

Smaller, but no less impressive is Pontsarn Viaduct. This was also designed by Alexander Sutherland and built by Savin and Ward to bridge the Taf Fechan Valley. Opened in 1867, Pontsarn is 455 ft long and 92 ft high at its highest point and comprises seven arches. Unlike Cefn Viaduct, it is built entirely of limestone.

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Pontsarn Viaduct courtesy of Old Merthyr Tydfil (http://www.alangeorge.co.uk/index.htm)

The Merthyr to Brecon Line stopped carrying passenger trains in 1961, but goods trains continued to use the viaducts, with the last train crossing them on 1 August 1966. Both viaducts are now Grade II* listed and form part of the Taff Trail.

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