Engineers working to renew the railway in Glasgow Queen Street tunnel have completed the first line of track through the 1km-long structure.
The £60M project is the largest piece of engineering work on the Edinburgh-Glasgow railway since it was built in the 1840s, according to Network Rail.
Network Rail said that since the high level station closed to trains on 20 March, over 2,100 engineers had invested more than 150,000 work hours to renew track through the tunnel and to lengthen and rebuild platforms and track layouts within the station.
The 20-week scheme has now completed the first line of new slab-track and Network Rail said that it remained on course to reopen the station on 8 August.
Work has now begun on laying the second line of new slab-track through the tunnel.
Over the last 10 weeks Network Rail engineers, who are renewing the tunnel for the ScotRail Alliance, have removed over 5,000t of concrete and rock, created a new 945m concrete base and installed 820m of new slab-track units and 2,000m of new rail.
“We have now passed the halfway point in this vital project and our engineers have completed a huge amount of work as they stay on course to reopen the tunnel for passengers on 8 August,” said ScotRail Alliance infrastructure director David Dickson.
“The renewal of the tunnel track, and the installation of overhead power equipment, will allow the introduction of faster, longer and greener trains on the main Edinburgh-Glasgow line – delivering thousands of extra seats, shorter journey times and improved accessibility for customers.
“Although, this is a massive engineering challenge it has been meticulously planned and we’d like to thank customers for their support and understanding while we deliver this investment in Scotland’s railway.”
The tunnel renewal is being delivered by engineers working on the Edinburgh Glasgow Improvement Programme (EGIP) to electrify the main Edinburgh-Glasgow line.
Through EGIP, 70 Hitachi Class 385 electric trains will be rolled out on a number of routes by December 2018. These will allow ScotRail to run trains of up to eight carriages on the main Edinburgh-Glasgow line once the new Glasgow Queen Street station is complete.