RAILTRACK HAS put a 20mph speed limit on a 1.5km section of the East Coast Main Line at Dolphingstone in East Lothian after fears of subsidence caused by abandoned mine workings.
An assessment of the area is under way to help engineers decide what remedial works will be needed to repair the section of track.
A Railtrack spokesman described the speed limit as 'precautionary' but said that the track had been put under round the clock monitoring. On-board equipment is also being used on trains.
Engineering options to solve the problem are likely to include grouting, installation of a geotextile blanket, track bed replacement or use of a reinforced concrete slab. All will involve constructing a temporary diverted railway.
A similar problem in 1999 prompted Railtrack to spend £6M relaying the track bed at Wallyford, 1km from Dolphingstone.