HS2 has completed the installation of the second of two rail viaduct decks across the M6 near Chelmsley Wood, completing the M6 South viaduct structures. 

The 4,750t west deck was pushed 76m into its final position above the northbound and southbound carriageways near junctions 4 and 4a on Saturday 24 October.  

According to HS2, engineers from Balfour Beatty VINCI took nine hours and used hydraulic strand jacks to move the steel structure at an average speed of 12m/h. 

The motorway remained open during the work. However, the M42-M6 link road was shut to establish a safety exclusion area and reopened at 9pm on 24 October, 25 hours ahead of the scheduled reopening time. 

The newly installed deck will carry trains towards Birmingham Curzon Street and destinations to the north, including Manchester, Liverpool and Glasgow, HS2 said.  

The parallel east deck, completed in 2025, is intended for services travelling towards Old Oak Common and Euston. 

Both 320m structures are made from weathering steel and sit on concrete piers. They run 100mm apart, with raised embankments due to be constructed on either side. 

The team assembled and launched the two decks in separate stages due to site constraints, installing the west deck in four incremental launches and moving the east deck into place in three. 

Under this method, crews attach additional steel sections to the rear before propelling the whole deck forward.  

At the final stage, piers on both sides of the motorway support the deck's weight. 

HS2 senior project manager Ian Clarke said: “These viaducts straddle some of the busiest sections of motorway in the country, which is why we adopt innovative techniques that allow construction to continue without closing the carriageway whenever we can. 

“We have made great progress this year and I thank motorists and local communities for their patience.” 

Strong winds postponed separate work to install parapets on the Water Orton viaduct above the M42. The work had been rescheduled for the following weekend. 

The change means the northbound carriageway between junctions 6 and 9, and the southbound carriageway between junctions 9 and 7, are due to close from 9pm on Friday 30 October until 5am on Monday 2 November 2026. 

HS2 said its 2027 motorway construction programme would focus on the triple box, a rail-over-road structure intended to carry four HS2 tracks across the M42 near Coleshill.  

The company is working with National Highways on the schedule.