Loughor Viaduct

[2] The Loughor viaduct was constructed to carry the broad gauge South Wales Railway (SWR) west of Swansea to Carmarthen.

[3] The viaduct was rebuilt several times; modifications made include the removal of its swing bridge and broad gauge tracks, replacement of the timber deck with an iron structure, and additional piles.

In 1986, due to structural concerns, the track was singled and speed restrictions were imposed adding to journey times.

c. cxc) received royal assent and the South Wales Railway (SWR) began construction of the line.

[2] Lavington Evans Fletcher, Brunel's assistant and the resident engineer, designed the movement mechanism for the swing bridge.

To prevent river traffic being obstructed, the viaduct had a 40 ft opening swing bridge at the Swansea (east) end.

[3] The deck supports were changed, longitudinal wrought iron girders were replaced with deeper steel plate.

[3][2] It was discovered that the river bed beneath the viaduct had been severely eroded necessitating the addition of tipping stones to protect the timber.

Freight and passenger trains were subject to speed restrictions, which led to delays and longer journey times.

[7] The viaduct is on a five-mile section of railway between Cockett and Duffryn, which was reduced from double to single track operation during 1986.

The deck is a shallow slab, supported by deeper main girders, allowing the level to match its predecessor.

[9] The replacement bridge had to address operational, heritage and environmental concerns which influenced the methods of construction and other decisions.

Once completed, the new bridge was slid sideways into position using hydraulic jacks over 14 hours after the viaduct had been speedily demolished.

[9] As the old viaduct had been Grade II listed, efforts to preserve it for historical reasons were integrated into the replacement plan.