The M6 through Cumbria has reopened 13 hours earlier than planned after the successful installation of a 4,200-tonne railway bridge over the motorway this weekend.

Clifton railway bridge near Penrith has been replaced by Network Rail and its principal contractor Skanska as part of a £60m investment to make the West Coast Main Line fit for the future.

On Saturday (10 January), the new 130-metre-long structure was carefully manoeuvred into place with millimetre precision.

The new pre-built bridge – which has been waiting in the wings after the old structure was demolished the previous weekend – was driven into place by specialist machines with more than 600 wheels.

To allow the huge civil engineering project to take place, two unprecedented 60-hour closures of the whole motorway were scheduled between junctions 39 and 40 over consecutive weekends.

Despite sub-zero temperatures and bad weather, work went so well that the motorway reopened shortly before 4pm on Sunday 11 January – 13 hours ahead of schedule –allowing the National Highways diversionary routes lifted much earlier than planned.

Last weekend both north and southbound carriageways also opened 70 minutes early.

Christian Irwin, Network Rail North West and Central region capital delivery director, said: “It’s a testament to the hard work of hundreds of people that we’ve been able to install this huge new structure both successfully and speedily. We’ve been in close contact with National Highways throughout so we could capitalise on that and get the M6 reopen over half a day ahead of schedule to alleviate pressure on local roads.

Steve Mason, National Highways programme delivery manager, added: “This is the first time in recent memory the M6 has been closed for whole weekends and follows years of careful planning with Network Rail. Some 48,000 vehicles use this section of the M6 daily but we chose a time of the year when traffic volumes are at their lowest.

“This was an incredibly complex operation and reopening the M6 13 hours early is a tremendous achievement. Despite severe weather conditions, the teams involved worked tirelessly to deliver this vital, one-in-a-lifetime project to future-proof one of the most important railway lines in the country.”

Rosario Barcena, Skanska UK rail programme director, said: “Over the course of the weekend, we’ve worked closely with Network Rail and National Highways to re-prioritise our work in order that we could re-open the motorway much earlier than planned. Before midday this was for emergency services, and now to all road-users.

“It’s been achieved thanks to our whole team, including our amazing supply chain partners. They’ve worked tirelessly across the weekend to successfully install the new Clifton railway bridge, a hugely complex and precise operation, and now re-open the motorway.”

Teams are now busy installing new track and reconnecting overhead power lines and signalling systems over the renewed structure.

While that takes place the railway remains closed between Oxenholme and Carlisle until start of service on Thursday 15 January.

This ongoing project is just one of a raft of journey improving upgrades between London and Cumbria over the festive season.

The Christmas and New Year work has seen a combined investment of nearly £200m along the West Coast Main Line, which forms part of a much larger £400m investment over the next four years.