HS2’s ambitious civil engineering programme is set to shift up a gear this summer, as it prepares to deliver its most extensive programme of work yet over the motorway network.
The construction schedule, commencing in June, will see three enormous structures built over busy stretches of the M42 and M6 in the West Midlands.
In one operation, a twin box will be constructed above both carriageways of the M42 near Birmingham Business Park – enabling the railway to be built over the top. In addition, two single-track viaducts will be extended over the M42/M6 Toll near Water Orton, and a twin-track viaduct will be installed over the M6 near Chelmsley Wood.
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The sheer scale of the engineering works will highlight the progress being made on HS2, as viaducts and structures built for the railway – which have been taking shape alongside the road over the past year – begin to span the carriageway.
HS2 Ltd and its civil engineering partner, Balfour Beatty VINCI (BBV), have spent more than a year planning the motorway crossings in conjunction with National Highways, with every effort made to minimise disruption and keep traffic flowing.
The six-month schedule was originally planned with nine closures, but the team has synchronised the majority of the work on the twin box structure and the Water Orton viaducts into the same weekends. This planning has reduced the total number of motorway closures from nine down to six. To reduce disruption for commuters during busy periods, junction closures will only take place from 9pm on Friday evenings through to 5am on Monday mornings.
While the schedule of motorway works indicates that headway is being made, there remains a considerable amount of work to complete across the 140-mile route between London and Birmingham.
Mark Wild, HS2 Ltd Chief Executive, is leading a comprehensive reset of the project to ensure the remaining stretch of the route is delivered as efficiently as possible and for the lowest reasonable cost. Minimising disruption to communities and working more productively remains a clear priority.
Agnes Usciak, HS2 Ltd’s Senior Project Manager for the works, said: “The progress we’re making on the viaducts and structures next to the M6 and the M42 is already clear to see, and over the next six months, we’ll start bridging the gaps above the carriageways.
“It’s been a huge team effort to condense this vast programme of work into just six weekend closures, and I’d like to thank all our partners for their co-operation and support.
“Safety will always be our number one priority, which is why we need to divert traffic away from the carriageway while we conduct these vital works.” Overhead works on the M42 are set to commence on the evening of Friday, 26th June 2026, with the installation of the roof deck for the twin box. This 300-metre-long structure will enable the high-speed rail line to be constructed over the M42, and once finished, vehicles will pass through the box while trains run overhead.
The walls of the twin box are being erected using a modular construction method, with these works progressing rapidly without the need to close the motorway.
The roof deck will be built over four weekend closures, during which engineers will install 175 individual beams, each weighing between 56 and 92-tonnes. These enormous beams, manufactured off-site in Leicestershire, will be lifted into position using a 300-tonne crawler crane.
Simultaneously, engineers in nearby Water Orton are preparing to extend two single-track viaducts that will carry high-speed trains into Birmingham Curzon Street and the rolling stock depot at Washwood Heath.
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Already approximately 1,200 metres in length, the team will employ a different construction technique to complete the remaining 135-metre sections of the Water Orton 1 and 2 viaducts, which will bridge the gap between the piers on either side of the motorway. Rather than continuing with the cantilever construction method, the viaducts will be prefabricated in sections alongside the carriageway – removing the need for further closures. Once fully assembled, they will be manoeuvred into position using self-propelled modular transporters and secured above the piers. This approach significantly reduces installation time, enabling engineers to complete the works across just four weekends. This programme of work will commence at 9pm on Friday, 24th July 2026.
The final construction challenge – the installation of the M6 South Viaduct West – requires just one weekend motorway closure, as two stages of the fully restrained slide process will take place over live traffic, eliminating the need to close the carriageway. The single weekend closure will commence at 9pm on Friday, 21st August 2026.
Oliver Shore, Project Director at Balfour Beatty VINCI said: “We achieved a UK first last year, when we slid a viaduct into place over a live motorway, and we’re delighted to be given the opportunity to repeat the process again this year over the same stretch of the M6.
“Engineering innovations and extensive planning have played a major role in our approach to this vast programme of work, above the M6 and M42, and we’ve made every effort to minimise impacts for motorists and communities.” As well as serving as busy commuter corridors between Birmingham, Warwickshire and Solihull, the M6 and M42 carry millions of travellers to and from Birmingham Airport and the National Exhibition Centre (NEC) for both work and leisure purposes.
Over the past five months, HS2 Ltd and BBV have worked in close cooperation with Birmingham Airport and the NEC Group to plan for the works, acknowledging the potential disruption this could cause to their customers.
In the coming weeks, HS2 and BBV will host a series of community events, alongside National Highways, to ensure that residents, businesses and commuters are fully informed of the planned closure dates and the approved diversion routes that will be put in place.
Digital toolkits, comprising maps and guidance notes, have also been produced to keep businesses, communities and motorists up to date.
Ian Doust, National Highways’ Head of Network Planning and Development, said: “A key priority for us is minimising disruption for those who use our roads so we welcome the measures being taken by HS2 and their partners to reduce the impact of this huge infrastructure project on road users.
“We recognise that there will, inevitably, be some disruption during these weekend closures so we would advise people to leave extra time for journeys and take alternative routes if at all possible.” HS2 is revealing all closure dates for the entire year to provide motorists with ample time to plan ahead. The initial closure will occur in five weeks’ time, on Friday, 26th June 2026.
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