HS2 has announced a world-first as around 450 people from HS2's construction contractor in the Midlands, Balfour Beatty VINCI (BBV), slid a 12,600 tonne bridge a record 165 metres to position it across a motorway in Warwickshire.

The site team worked around the clock to move HS2's Marston Box bridge into place over the M42 during the Christmas period. The operation took 40 hours, at a speed of 4 metres per hour, from Saturday 24 to Monday 26 December during a 10-day closure of the motorway between Junctions J9 and J10 (northbound and southbound). The motorway is on schedule to reopen at 0500 on Tuesday, 3 January 2023.

Rail Minister Huw Merriman said: "This is yet another astonishing achievement by HS2 - a project which is already changing lives through employment and regeneration, and will completely transform the way we live and work once trains hit the tracks.

"Thank you to the 450 people working over the Christmas period on this incredible operation, who are playing their part in bringing this pioneering project to life. What a way to end the year."

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HS2 Ltd's Civils Delivery Director, Mike Lyons said: "This is the first box slide of its kind over a motorway in the UK, and we believe it’s also the world’s longest slide, so it’s a great achievement for HS2 as we quickly approach peak construction. It’s fantastic to celebrate another big milestone for a project that is already providing work for almost 30,000 people today, and in the future, it will encourage people to use zero carbon public transport."

Over the last six months, the giant 86 metre-long structure was built on land next to the motorway. The structure, developed by a Design Joint Venture of Mott MacDonald and Systra, working on behalf of BBV, has a base, three walls and top slab.

The sliding mechanism, designed by specialist civil and structural engineering company Freyssinet, allowed the box to be pushed into place over the motorway on a guiding raft over a distance of 163 metres – which is believed to be the world's longest box slide.

On completion, the whole structure will be around 190 metres in length, and will carry HS2 over the motorway as it heads north to Crewe, or on its southward journey as it loops into Birmingham Curzon Street or continues straight on to Interchange Station in Solihull, Old Oak Common Station and London Euston.

Once built, the railway bridge will connect to Dunton Wood Embankment to the south and the Birmingham and Fazeley Canal Viaduct, which crosses the heritage canal, to the north.

This construction method, which allowed it to be moved into place in one movement meant only two one-week closures of the motorway over a 12-month period, dramatically reducing disruption for road users.

The box slide operation is part of HS2's 550,000 square metre site at Kingsbury, where over 1,000 people are currently working. Around 6,800 people are already employed in HS2's construction in the West Midlands, with thousands more jobs supported through the wider supply chain.