Qualla: Walnut Tree Viaduct

Walnut Tree Viaduct: Introduction

Sat, 23 May 2026 00:00:00 GMT

Photo credit Gareth James, CC BY-SA 2.0. Drive south from Pontypridd on the A470 toward Cardiff and you will pass, on the right just north of Radyr, two solitary brick pillars rising out of nothing. They look like the entrance gateposts to a vanished estate. They are in fact what is left of the Walnut Tree Viaduct, a steel-girder structure 1,548 feet long and 120 feet high that crossed the River Taff at Taffs Well from 1901 to 1969. The road improvements of the 1960s needed the line that the viaduct stood on, and the demolition crew that spent five years dismantling the piers had to do most of the work by hand because the valley was too congested for heavy machinery. By 1974 there was nothing left of it but the two pillars, kept because the contractors could not quite work out how to take them down without damaging the road.

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Image: Gareth James | CC BY-SA 2.0

Walnut Tree Viaduct: Breaking the Bute Monopoly

Sat, 23 May 2026 00:00:00 GMT

Photo credit Mary Gillham, CC BY 2.0. The viaduct was born of frustration. By 1880 the Taff Vale Railway and Cardiff Docks - both controlled by the Marquess of Bute and his estate - had become the only practical export route for South Wales coal. Pontypridd station was a bottleneck. The single double-track line south...

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Image: Mary Gillham | CC BY 2.0

Walnut Tree Viaduct: The Llanbradach Branch

Sat, 23 May 2026 00:00:00 GMT

Photo credit Duncan and Gareth Alderson, CC BY-SA 2.0. Davies wanted more. He wanted access to the Rhymney Valley and the great iron works at Dowlais up at Merthyr Tydfil. So the Barry Railway proposed a branch from its main line at Tynycaeau Junction near St Fagans, running northeast through Walnut Tree across the Taff valley to a j...

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Image: Duncan and Gareth Alderson | CC BY-SA 2.0

Walnut Tree Viaduct: Steel, Not Stone

Sat, 23 May 2026 00:00:00 GMT

Photo credit Mary Gillham, CC BY 2.0. Szlumper studied the Crumlin Viaduct, Charles Liddell's earlier iron triumph forty years east. He reached the same conclusions: a stone bridge of this height would create dangerous wind compression around its piers, and importing the stone would be expensive because the local roc...

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Image: Mary Gillham | CC BY 2.0

Walnut Tree Viaduct: The Short Glory

Sat, 23 May 2026 00:00:00 GMT

Photo credit Mary Gillham, CC BY 2.0. The Llanbradach branch had a short life. The Great Western Railway absorbed the Barry Railway in 1922 under the grouping that consolidated Britain's railways into four large companies. By the early 1930s the GWR had decided the line north of Penrhos Lower Junction was redundant. ...

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Image: Mary Gillham | CC BY 2.0

Walnut Tree Viaduct: Down by Hand

Sat, 23 May 2026 00:00:00 GMT

Photo credit Mary Gillham, CC BY 2.0. The A470 road improvements made the demise certain. Two of the viaduct's brick pillars stood directly in the path of the planned new road. Demolition began in 1969 and dragged on until 1974. The valley bottom was too congested for cranes and explosives - the railways below were s...

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Image: Mary Gillham | CC BY 2.0