Conwy Railway Bridge

Conwy Railway Bridge Pont Rheilffordd Conwy
Conwy Railway Bridge across the River Conwy
Coordinates	53°16′49″N 3°49′25″W / 53.280278°N 3.823611°WCoordinates: 53°16′49″N 3°49′25″W / 53.280278°N 3.823611°W
Carries	North Wales Coast Line
Crosses	River Conwy
Locale	Conwy
Maintained by	Network Rail
Heritage status	Grade I listed
Cadw	3236
Followed by	Conwy Suspension Bridge
Characteristics
Design	Tubular bridge
Material	Wrought iron Limestone
Total length	463 ft (141 m)
Width	42 ft (13 m)
Clearance below	46 ft (14 m) (low tide)
Design life	1899: cast iron piers are added to reduce the load on the tubes and permit heavier trains
History
Architect	Francis Thompson
Engineering design by	Robert Stephenson in collaboration with William Fairbairn and Eaton Hodgkinson
Constructed by	William Evans
Construction begin	1846
Construction end	1848
Opened	1849

The Conwy Railway Bridge carries the North Wales coast railway line across the River Conwy between Llandudno Junction and the town of Conwy. The wrought iron tubular bridge, which is now Grade I listed, was built in the 19th century by Robert Stephenson. It is the last surviving example of this type of design by Stephenson after the Britannia Bridge across the Menai Strait was destroyed in a fire in the 1970s.

History

The bridge was constructed to carry the Chester and Holyhead Railway across the River Conwy. Robert Stephenson, in collaboration with William Fairbairn and Eaton Hodgkinson, provided the engineering plans. Before their involvement it was intended to be a suspension bridge; complimenting the 1826 Conwy Suspension Bridge by Thomas Telford. However after Stephenson was appointed chief engineer, the design changed because he understood that suspension bridges were not robust enough to carry trains. Faced with the challenge of bridging the River Conwy in a single span, Stephenson and his collaborators invented wrought-iron box-girder construction. Proved here they could apply it to the far greater challenge along the line of building the Britannia Bridge across the Menai Strait).

The second wrought-iron box girder tube is floated into position, c. September 1848.

The project's architect was Francis Thompson who dressed the pylons at either end as barbicans, complete with crenellated turrets, arrow slits and bartizans to complement the adjacent Conwy Castle, an Edwardian fortification that had stood on the promontory since the late 13th century. The bridge contractor was a William Evans. Construction began in 1846. The ironwork was constructed by Easton & Amos.^[1] Steam-powered hydraulic engines were used to lift the wrought iron girders and beams into place from barges moored in the river.

The bridge was officially opened in 1849 although it had been completed in 1848. As the first tubular crossing to be built, Stephenson wanted to confirm through testing that the structure would be capable of carrying the weight of a locomotive and its rolling stock. The testing was performed by Fairbairn. The successful results endorsed the construction of the Britannia bridge. In 1899 the tubular sections were reinforced with additional cast iron columns to reduce the load on the span across the river.

Legacy

Conwy railway bridge remains the only surviving example of a tubular bridge designed by Stephenson. The original Britannia Bridge was consumed by fire in 1970. Although it was subsequently rebuilt, it was reconstructed as a two-tier truss arch bridge made from steel and concrete.

The bridge is maintained by Network Rail because it is still part of the UK rail system. Its heritage is managed by Cadw.

See also

• List of bridges in Wales

Notes

Citations

1. Hebert & 1849 2

Bibliography

• Hebert, Luke (1849). The Iron Tubular Bridge Over The River Conway. The Engineer's and Mechanic's Encyclopaedia. Vol 1 (2nd ed.). Thomas Kelly: London.

External links

• Aerial photo
• Local tourist information
• General description of the Britannia and Conway tubular bridges on the Chester and Holyhead Railway, 1849, from Google Book Search