Britannia Bridge

The Britannia Bridge carries trains and road traffic across the Menai Strait between Anglesey and the mainland. It stands where the strait narrows, a mile east of the older Menai Suspension Bridge. Robert Stephenson designed the original railway bridge in the 1840s as two wrought-iron tubes big enough for locomotives to run inside. The tubes weighed 1,500 tonnes each and spanned 460 feet, far longer than any iron span before. William Fairbairn ran experiments in his London shipyard to stiffen the plates, while Eaton Hodgkinson studied how the tubes would resist buckling under heavy loads. A 75-foot model was built and tested before work began on the full-sized bridge. The bridge became the final link in the Chester and Holyhead Railway, letting trains run from London to Holyhead and on to Dublin. Admiralty rules forced the bridge high enough for tall ships to pass underneath. Stephenson supervised the laying of the foundation stone in 1846 and drove the last rivet in 1850, marking its completion. For over a century it carried only trains, but a fire in 1970 destroyed the iron tubes beyond repair. Engineers rebuilt the piers and added two new steel arches to carry both rail and road traffic. Today the rebuilt bridge has two decks, one for trains and one for cars and lorries. The stone piers still stand where Stephenson placed them on the Britannia Rock. Visitors crossing the bridge see the strait below and the hills of Anglesey and Gwynedd on either side. The older suspension bridge lies a short distance away, showing how two bridges serve the same crossing in different ways. The bridge remains an important route for both rail and road between north Wales and the rest of the country.