Engineers have completed the installation of the second HS2 viaduct over the M6 at junction 4/4a near Chelmsley Wood in Solihull, West Midlands.
The final section of the westbound steel deck was moved into place on Saturday 24 October using hydraulic strand jacks. The operation, carried out by HS2 main works contractor Balfour Beatty Vinci (BBV), took about nine hours while traffic continued to use the motorway.
The 4,750t deck was pushed forward 76m at an average speed of approximately 12m an hour. Its completion means both of the M6 South viaducts are now structurally finished.
Parallel viaducts
The east deck was completed earlier in 2025 and will carry trains towards HS2’s London terminus at Old Oak Common and Euston. The newly installed west deck will carry services towards Curzon Street in Birmingham and destinations further north, including Manchester, Liverpool and Glasgow.
The two parallel weathering-steel structures are each about 320m long and sit approximately 100mm apart. Concrete piers support the decks, which will be flanked by raised embankments.
BBV said the west deck was launched in four stages, compared with three for the east deck, because of constraints at the site. Additional steel sections were added to the rear during each stage before strand jacks propelled the structure forward until its weight was supported by piers on either side of the motorway.
The M42–M6 link road was temporarily closed to create a safety exclusion zone during parts of the work. It reopened at 9pm on Saturday, around 25 hours earlier than planned, while the M6 remained open throughout the weekend.
Further motorway works
Strong winds led to the postponement of scheduled parapet works at the nearby Water Orton viaduct over the M42. The works have been rescheduled for the weekend of 30 October to 2 November and will require overnight closures between junctions 6 and 9, and junctions 9 and 7, from 9pm on Friday to 5am on Monday.
HS2 is due to focus next year on completing a “triple box” rail-over-road structure carrying four HS2 tracks over the M42 near Coleshill. HS2 Ltd said it was coordinating the programme with National Highways.
Russell Luckhurst, BBV engineer leading delivery of the work, said: “Two neighbouring viaducts that run parallel to each other now span the busy M6 motorway near Chelmsley Wood, after the west deck was safely and successfully moved into its final position over the weekend.”
He added: “It’s a huge moment for Balfour Beatty Vinci and HS2, concluding a major programme of work above the M6 – in extremely challenging weather conditions.”
HS2 Ltd senior project manager Ian Clarke said the viaducts crossed “some of the busiest sections of motorway in the country” and that innovative construction methods were used to avoid closing the carriageway where possible.