In a major milestone for UK infrastructure, engineers working on the HS2 project have successfully reopened the M6 motorway ahead of schedule after sliding a massive section of a new viaduct into place—demonstrating the kind of precision and collaboration that defines modern rail and road engineering.
Over the weekend, the 230-metre East Deck of the twin viaducts was carefully manoeuvred across the M6 near Birmingham Airport. The operation required a full closure of both northbound and southbound carriageways, but thanks to meticulous planning and execution, the road was reopened 9.5 hours earlier than expected.
This marks the first time the HS2 team in the West Midlands has used a ‘fully restrained’ sliding technique. The method, developed in partnership with National Highways, allowed the viaduct to be launched over the M6 Junction 4 slip road while keeping traffic flowing underneath—a significant innovation aimed at reducing disruption for road users.
Caroline Warrington, HS2 Ltd’s Head of Delivery, praised the achievement:
“This is a major feat of engineering over a vital section of the UK’s transport infrastructure, so to be able to reopen the road early is a fantastic achievement. These viaducts will be pivotal to the HS2 network, carrying high speed trains over the M6 and creating better journeys for people for many years to come.”
The twin 320-metre viaducts are being built in phases to minimise disruption. Each section is assembled adjacent to the motorway and then pushed into position, with the next segment added behind it. This staged approach means the structure’s weight will eventually reach 4,645 tonnes.
The operation is being led by HS2’s main works contractor, Balfour Beatty VINCI (BBV), supported by Victor Buyck Steel Construction (VBSC). It follows a successful first phase completed in June and sets the stage for the final launch of the East Viaduct later this year.
Russell Luckhurst, the BBV engineer overseeing the works, said:
“This weekend, we successfully delivered the second phase of a complex operation to launch a huge viaduct over the M6 motorway. Thanks to the team’s hard work and engineering expertise using new techniques, we were able the reopen the northbound carriageway on Saturday evening and then the full motorway was open again from Sunday lunchtime – which was great news for road users in the area.
“Assembly of these viaduct decks is taking place offline next to the motorway, and are being launched in three phases, to reduce disruption on the road network. Our focus is now on the third and final launch of the East Viaduct, which is planned for later this year.“
The team worked closely with National Highways and local stakeholders including Birmingham Business Park, the NEC, and Birmingham Airport to coordinate the closure and minimise impact.
Kamaljit Khokhar, National Highways’ Head of Planning and Development for the Midlands, commented:
“Our focus with any scheme is to minimise the impact on people using or living near our roads while ensuring the work is carried out safely and efficiently. We have worked closely with HS2 and their construction partners to do all we can to limit the disruption this huge infrastructure project will inevitably bring.
“We are pleased to see how well the work went at the weekend and applaud the innovative techniques HS2 has introduced which have significantly reduced traffic restrictions on this key route by constructing the structure next to the road.”
The viaduct was moved using strand jacks—winches that pulled the structure at an average speed of ten metres per hour. To reduce friction, engineers used non-stick pads made from a material commonly found in frying pans. Rollers placed on the piers ensured the deck stayed on course throughout the slide.
Each viaduct is built from a hollow double-box structure made of weathering steel, which forms a protective oxidised layer, reducing the need for repainting. Four pairs of concrete piers support the viaducts, with the tallest reaching 9.9 metres. A 4.5-metre high parapet will be installed on the Chelmsley Wood side to reduce noise from passing trains.
The East Deck was launched with 51 precast slabs already installed, helping to reduce future road closures and streamline the completion of deck works.
As HS2 undergoes a strategic reset under CEO Mark Wild, this successful operation highlights the project’s commitment to efficiency, innovation, and collaboration—values that resonate across the UK rail industry.
Image and video credits: HS2
