Tubular Railway Bridge

Cadw's description

Location

Spanning Afon Conwy on the E side of the castle and S of the modern road and suspension bridges.

History

On the Chester-Holyhead Railway, built 1846-49 by Robert Stephenson, in collaboration with William Fairbairn and E. Hodgkinson. The architect was Francis Thompson, the contractor William Evans. It was originally intended to be a suspension bridge. The bridge, like Stephenson's contemporary Britannia Bridge spanning the Menai Strait, pioneered wrought-iron box-girder construction. Intermediate piers were added in 1899.

Exterior

A tubular railway bridge between ashlar rectangular castellated towers (originally intended for carrying the chains of a suspension bridge), with blind arrow loops, and an embattled parapet on corbelled machicolations. Lower round turrets to the outer corners have a Lombard frieze to the parapet, and smaller corbelled round turrets to the inner corners have a Lombard frieze to conical caps. The outer sides have a pair of round-headed arches with continuous chamfer. On the inner sides are vents with latticework iron grilles above the girders.

The deck is double-track, each track having its own tubular girder construction, and incorporating a travelling crane. Set back from each end are 2 round concrete-filled cast-iron piers added in 1899.
The approach on the E side has a rock-faced coped wall to a polygonal terminal pier. Beyond, the NE side has a later plainer wall.

Reason for designation

Listed grade I as a major work of C19 civil engineering of national importance.