HS2 Prepares for Next Major Viaduct Launch Over M6

Engineers working on the West Midlands section of HS2 are preparing to install the next section of a major viaduct spanning the M6 near Chelmsley Wood.

The structure forms part of the M6 South viaduct, which will carry high-speed trains towards Birmingham. The westbound deck is being constructed in four separate sections, with the first 107-metre segment scheduled to be moved into position over the M6 junction 4 southbound slip road on 11 April 2026.

Contractor Balfour Beatty VINCI (BBV) expects the operation to take around two days. Using a hydraulic jacking system, the 1,250-tonne steel structure will be gradually pushed across the motorway, sliding into place over pre-built piers before being secured.

To facilitate the work, the slip road will close from 5am on Saturday, with reopening planned for 10pm on Sunday following final safety checks by the project team.

Once complete, the 320-metre west deck will sit alongside the east deck, which was successfully installed in stages during 2025. That earlier installation included a UK-first approach, with sections of the viaduct slid into place while traffic continued to flow beneath.

Building on that success, HS2 and National Highways are continuing to work together to minimise disruption, aiming to carry out as much of the remaining installation as possible without closing the main carriageway.

However, the west deck presents additional engineering challenges. Limited space, curved alignments and the positioning of supporting structures mean the viaduct must be assembled in smaller sections than its counterpart, requiring an additional stage in the installation process.

The project team has already fitted a launching nose to guide the structure and is now finalising the propulsion system that will drive the slide operation.

This latest phase marks the beginning of a busy period of construction activity, as HS2 progresses work to carry the railway across key motorway routes in the West Midlands. While some works later in the year may require further traffic management on the M6 and M42, efforts are ongoing to limit disruption wherever possible.

National Highways has confirmed it is working closely with HS2 to ensure road user safety remains a priority while keeping closures to a minimum during the programme.