A storm-damaged rail bridge will reopen after a major project to save it from collapse.

Train services will resume running over the Lamington Viaduct in South Lanarkshire on Monday, February 22.

The Victorian structure was severely weakened left close to falling into the River Clyde after Storm Frank wreaked havoc on Hogmanay.

Its second pier was left on the brink of collapse when water scoured out much of its foundations.

The bridge carries the railway, running between Carstairs and Lockerbie, across the River Clyde. It is a section of the West Coast Main Line between Glasgow and London, where passenger trains are permitted to travel at up to 120mph.

It emerged last month that engineers called in to inspect the bridge after the storm had lifted a speed restriction, allowing a high-speed train to cross just minutes before finding a further fault. The Rail Accident Investigation Branch (RAIB) had launched an inquiry into the case.

The ScotRail Alliance revealed on Monday that an extensive seven-week engineering project to repair and reopen the viaduct will finish ahead of schedule.

Phil Verster, managing director of the ScotRail Alliance, said: “I am delighted that we have managed to complete the works at Lamington ahead of schedule.

“I understand the impact the closure of Lamington Viaduct has had on customers and our engineers have been working around the clock since its closure to finish the repairs and get trains back on the West Coast Main Line.

“This project has been a hugely challenging one - involving working out in the Clyde through the worst of January's storms in a race against time to save the structure.

"Our engineers have faced atrocious conditions throughout this project and I am really proud of their hard work and their absolute commitment to getting the line open again.

“I really do want to thank customers for their patience and our industry partners for the close cooperation shown over the last two months.

"By working together we have been able to help limit disruption for passengers by providing diversionary routes for many of the affected services.”

Engineers had to work fast to divert the Clyde and stabilise the structure following Storm Frank.

The incident also damaged the second pier’s steel bearings, which support the bridge deck and track above the pier, a non-load-bearing section of the viaduct’s third pier and the structure’s north abutment.

Over the weekend, engineers installed new steel bearings on the viaduct’s damaged second pier and constructed a new concrete plinth on the top of the pier to support them.

After the bridge deck was raised back into position, the recovery works are now progressing two weeks ahead of the March reopening date previously announced.

Improved weather conditions and the early arrival of new bearings for the bridge helped to accelerate the programme.

Phil Bearpark, executive director of operations and projects at Virgin Trains, said: "We’re really pleased that Network Rail has announced that the West Coast Mainline will reopen later this month, ahead of schedule.

"We would like to thank our customers for their continued support and understanding whilst the necessary repairs to Lamington Viaduct have been undertaken. It will be great to begin operating direct services to and from Edinburgh and Glasgow again and we look forward to welcoming our customers on board soon."

First TransPennine Express interim managing director Liz Collins said: "We know this disruption has been a difficult time for customers and our colleagues and we are grateful for their patience.

"Throughout the disruption we have been working hard with our industry partners to make sure customers can continue their journeys in and out of Scotland and this will continue while the final repair works are carried out."