AN innovative technique will be used to install a £3m road bridge on the outskirts of Durham.

Durham County Council is replacing the 19th Century Relley Bridge, which carries the B6302 over the East Coast Main Line, because it does not meet modern standards and cannot take 40-tonne European lorries.

The bridge's width and alignment are considered to be no longer suitable for modern needs and it has no facilities for pedestrians and cyclists.

A bridge will be built from reinforced concrete but it cannot be lowered into place by crane because of overhead power lines, the railway below, access difficulties and the bridge's 70-metre length.

"Instead, it will be winched sideways into position over the track so there won't be any danger of it fouling the pylons or the track," said a spokeswoman for the council.

"It will be the first time this technique has been used in County Durham.''

The bridge, which provides a link to the former pit villages of the Deerness Valley, will be built on site.

The existing bridge will stay open until its replacement, which will be installed at a different alignment, is ready for service, possibly in the summer.

It is one of a series of road bridges - not all of them over railways - across the county that are being replaced or strengthened because they are not up to standard.

The bridge will also have safety barriers, which have been installed at other bridges over the county's railways following the Selby crash.

The council's director of environment and technical services, Chris Tunstall, said: "The new Relley will provide a footpath and cycle track while the old road will be landscaped and planted with trees.

"The approaches to the bridge will also have safety barriers complying with current standards.

"Improving such barriers on bridges in the county is a priority for the council and we have carried out work at a number of road-over-rail sites that were shown to be sub-standard.''

The scheme, which got under way yesterday, will be carried out by the Durham Alliance for Civil Engineering, with Balfour Beatty taking the role of lead contractor.