M6 South Viaduct – Phases of Work

What we are doing

The M6 South viaduct will carry the new high-speed railway over the M6 motorway and adjoining slip road, near Birmingham Business Park, Birmingham Airport and the NEC in Solihull.

This section of the M6 Motorway is located near Chelmsley Wood, between junction 4 northbound and 4a southbound, as well as the M42 junction 7a northbound.

The south and north viaducts will span 314 metres on 8 piers and 4 abutments.

The viaducts will be constructed using the incremental launch method, which involves steel girders welded together on site, which are then pushed across each pier span. The girders will be anchored off the abutment and launching foundations. The construction of the viaducts will require 94 piles, 532 tonnes of steel reinforcement in the piers and 622m of steel girders to be driven during the launch.

This method of construction reduces the disruption for road users.

The East Deck will carry two tracks taking trains towards London while an adjacent ‘West Deck’ will carry a further two tracks for services heading to Birmingham and further north. We will first launch the East Deck of the viaduct in a series of Phases. We will then repeat these phases of work for the West Deck of the M6 viaduct.

Work started in Spring 2024 and will be ongoing until Summer 2026. There will be a number of M6 weekend road closures during these works.

Programme update  

Phase One – Completed June 2025

The first phase, successfully delivered over the weekend of Saturday 7 June -Sunday 8 June 2025, saw the East Deck of the M6 South viaduct slid 119m out over the M6 junction 4 off-slip adjacent to the motorway.

Time lapse footage of the East Deck of M6 South viaduct deck  launch June 2025

Phase Two – September 2025

Phase Two will involve the continuation of the East Deck being launched across the M6 northbound and southbound carriageways including the M42 junction 7a northbound link for the M6 southbound. To do this slide safely the M6 will be closed between junctions 4 to 4a northbound and junctions 4a to 4 southbound, including the M42 junction 7a to M6 southbound.

Full weekend closures will be from 3am on Saturday 27 September until 10pm on Sunday 28 September 2025 (subject to consents)

Before progressing the second launch of the viaduct, we need to carry surveys and essential works on the existing lighting columns located within the central reservation. To ensure the safety of our workforce while undertaking these activities there will be overnight lane closures between junction 4 and 4a from:

• 9pm to 6am on Tuesday 26 August and Wednesday 27 August and
• 9pm Monday 22 September to 6am Friday 26 September

Phase Three – December 2025/Early 2026

Further details will be shared once available.

Traffic management

To reduce the impact on the surrounding road network we work closely with National Highways to make sure the traffic management proposals have been designed and take into consideration any existing or planned traffic management in the area.

We are aware our works may impact road users travelling on M6 and the M42, and we work hard to minimise any disruptions through our planning processes. In addition to this we have put in place a recovery system throughout our work area.

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on: 08081 434 434 or email  [email protected]

Download information relating to these works

• Temporary overnight lane closures on the M6 motorway in August
• Temporary weekend closure on M6 northbound and southbound in September

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on 08081 434 434 or email [email protected]