Work on Britannia Bridge over Menai Strait starts
A £4m scheme to strengthen one of the bridges spanning the Menai Strait in north Wales is under way.
More than 50 engineers will be working round-the-clock for four months to improve both the railway and A55 road links on the Britannia Bridge.
In a bid to keep trains and vehicles moving a barge, abseilers and a movable platform will be used during the work.
The bridge was badly damaged by fire in 1970. It reopened to rail traffic in 1972, and the road was opened in 1980.
The scheme is a joint effort between Network Rail, the Welsh Assembly Government and the UK Highway Agency.
"Britannia Bridge is a landmark and a strategic gateway linking the isle of Anglesey to mainland Wales, carrying thousands of tonnes of road and rail traffic daily," said Mark Langman, route director for Network Rail.
Mr Langman said the work needed to be carried out to "keep the 160-year-old structure strong to serve Wales for many years go come".
"The bridge is uniquely located but we are determined to minimise disruptions and protect any rare plants and species within the conservation area while our work is being carried out," he added.
Engineers plan to replace eroded steel work, a faulty drainage system on the highway, old bridge parapets and stonework on the 830 metre (2,723ft) long bridge.
The steel portals on the approach to the bridge will also be painted, and a detailed inspection will be carried out in the internal chambers of the three towers.
A walkway is also planned to enable engineers to reach the structure to carry out ongoing inspections of the masonry piers.
A temporary traffic signal will be in place on the A55 between 1900-0700 GMT from 24 January and 24 April to allow the road work to be carried out.