New ‘super drain’ in tunnel fails to stop flooding on busiest rail line
Trains on Scotland’s busiest rail line were halted by a waterlogged tunnel despite a “super drain” being installed in the flooding blackspot four years ago, The Scotsman has learned.
Scotrail was also unable to use a previous diversionary route via Dalmeny because it was not electrified along with the Edinburgh-glasgow main line last year.
Network Rail Scotland (NRS) hopes to reopen the route through Winchburgh tunnel in West Lothian today after pumping out water 2ft deep.
However, Met Office heavy rain warnings for today and tomorrow have been extended into Sunday and now cover all of Scotland apart from the west Highlands and islands. Peak expected rainfall has also been increased from 40mm to 60mm.
NRS said that 60 per cent of the monthly rainfall had fallen in three hours around the tunnel, with trains unable to get east of Linlithgow since Wednesday night.
Around 20,000 passengers were disrupted, with Dunblane-edinburgh and Glasgow-edinburgh services via Cumbernauld halted at Falkirk Grahamston. Passengers were transported by bus.
However, it has emerged that work to tackle the tunnel’s chronic flooding problem was part of lowering the track by 8in to accommodate overhead power wires for the electrification scheme in 2015.
In her book Transforming the Railways of Central Scotland last year, rail author Ann Glen wrote: “825m (2,750ft) of new drains [were] formed, with a ‘super drain’ inserted between the tracks to try to cure the persistent wetness once and for all.”
She told The Scotsman:“they wanted to see to it that in the long term the tunnel would not cause repeated problems.”
Dr Glen said “slab track”, or concrete sections, were also laid under the rails to remove the problem of ballast being washed away by flooding. But NRS said this “managed” but had not “cured” drainage issues.
It said: “In excess of 50mm of rain fell in the area, overwhelming drainage in and around the railway.
“Work continues to pump flood water out of the full 330m length of the tunnel.”
A Scotrail spokesperson said: “We’ve been doing everything we can to keep customers moving.”
NRS said the West Highland line between Ardlui on Loch Lomond and Crianlarich would not now re-open until next Thursday after torrential rain washed away material under the track on Sunday.
The line between Crianlarich and Oban will re-open on Monday following repairs to separate rain damage.
The Scottish Environment Protection Agency issued 14 flood alerts over much of the country, with ground already saturated in many areas.
It warned of possible further flooding that could again disrupt transport.