Conwy Railway Bridge

Conwy Railway Bridge
Pont Rheilffordd Conwy

A Robert Stephenson Bridge Robert Stephenson's small Britannia Bridge in Conwy.

Conwy Railway Bridge across the River Conwy
Coordinates 53°16′49″N 3°49′25″W / 53.280278°N 3.823611°W / 53.280278; -3.823611Coordinates: 53°16′49″N 3°49′25″W / 53.280278°N 3.823611°W / 53.280278; -3.823611
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 1972. 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

Notes

Citations
  1. ↑ Hebert & 1849 2
Bibliography

External links

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