22 December 2025
A huge viaduct slide has marked a major milestone on the HS2 project in the UK. During the weekend of December 13-14, an enormous 4,600-tonne viaduct section was slid into place over the M6 motorway without closure to traffic in an operation marking another important stage for the HS2 project.
Placing of a new viaduct on the HS2 project in the UK

The M6 South Viaduct is one of the major structures of the Delta Junction, a triangular connecting area upstream of Birmingham between the HS2 high-speed network and the conventional railway network. This structure was designed by a consortium of Mott MacDonald and SYSTRA, in partnership with WW+P Architects.

A project at the forefront of safety and innovation

While the previous slide had required a weekend closure of the main carriageway, the team – led by HS2’s main works contractor Balfour Beatty VINCI (BBV) – worked closely with National Highways to develop the ‘fully restrained’ process which allowed them to safely slide the final section above the moving traffic. It is thought to be the first time this technique has been used on a UK motorway.

The dedicated design work that has been delivered enabled this innovative construction method to be successfully implemented, and it was a proud moment for everyone involved. Every element of work on the project was brought to life through a collaborative approach, and we look forward to next year’s progress.

Jack Hillier, Senior Project Manager at SYSTRA Ltd.

The M6 South Viaduct at the halfway stage

The 17-hour-long operation was the culmination of a three-stage process to install the 315-metre East deck of the M6 South viaduct, which will carry high-speed trains heading to Birmingham and further north.

This means the project to construct the M6 South viaduct has now reached the halfway point. Over the next year, the same process will be repeated, with a parallel West deck slid into position alongside the first one to carry trains heading south.

The M6 South Viaduct slide in images:

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