Engineers completed the complex process of jacking the track, which had dropped six inches, back into alignment over the course of this week.

Over the weekend work will take place to install the steel bearings on the viaduct’s damaged second pier. A new middle bearing will be hung from the underside of the bridge-deck and a new concrete plinth added to the top of the pier.

Engineers have taken advantage of a break in the weather conditions and the earlier than expected arrival of the new, custom-made, bearing to accelerate their recovery programme.

A new date for the reopening of the line is expected to be confirmed next week, once works to install the new middle bearing and place the weight of bridge-deck back onto its supporting piers are complete.

Stewart MacPherson, route delivery director for infrastructure projects, said: “Works to reopen the viaduct are progressing well with the structural damage below the waterline of the piers now stabilised and works well underway to realign and repair the bridge-deck.

“This has been an extremely complex and challenging project for our engineers who have had to work as quickly as possible to prevent the viaduct’s collapse and complete repairs in what have been extreme weather conditions.”

The Victorian-built viaduct was severely weakened and left close to collapse by flood damage during Storm Frank on New Year’s Eve.

Engineers had to work around-the-clock to divert the River Clyde and stabilise the structure after the viaduct’s second pier was left on the brink of failure when floodwaters scoured out much of its foundations.

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.