HS2 engineers prepare major M42 construction programme

By Danny BallPublished On: July 27th, 2026Categories: Top Stories

Engineers are preparing to deliver one of the most significant phases of HS2 construction over the Midlands motorway network this summer, with work taking place simultaneously on the Water Orton viaducts and the M42 twin box structure during a series of planned weekend closures.

The programme will see the high-speed railway extended across the M42 between Solihull and Water Orton, with HS2 Ltd and construction partner Balfour Beatty VINCI (BBV) coordinating complex engineering works alongside National Highways to minimise disruption for motorists.

Three major weekend closures are scheduled across July, August and September, with different traffic management arrangements depending on whether work is taking place on the northbound, southbound or both carriageways.

HS2 said more than a year of planning has gone into coordinating the motorway crossings, which form part of the 140-mile railway linking London and the West Midlands.

Twin box construction progresses over the M42

Work on the 300-metre-long “twin box” structure began in June, when around 150 engineers started a four-phase operation to install 175 precast concrete roof beams across both carriageways of the M42 near Solihull.

Once complete, the structure will carry HS2 trains above the motorway while traffic continues to travel beneath it.

During the first weekend closure in June, BBV and subcontractor Expanded installed 50 of the required beams, exceeding the original target by seven.

The next phase, beginning on 24 July, will focus on the northbound carriageway, with engineers aiming to install a further 44 beams before the motorway reopens.

Water Orton viaducts extended over motorway

Alongside work on the twin box, engineers will begin extending the two Water Orton viaducts across the M42.

Each viaduct is already around 1.2 kilometres long, with the remaining 135-metre gap over the motorway to be completed during the planned closures.

Ahead of installation, 108 precast viaduct segments are being assembled adjacent to the motorway to create six spans measuring 45 metres long and weighing around 1,000 tonnes each.

The completed spans will be transported into position using self-propelled modular transporters, with one span installed on each viaduct during the first closure.

Agnes Usciak, Senior Project Manager at HS2 Ltd, said: “This summer marks the most significant programme of work yet to carry HS2 over the motorway network.

“We have a huge engineering challenge ahead of us, and our engineers will be working day and night to extend three huge structures in tandem.

“Motorists travelling on the southbound carriageway will have seen the roof deck taking shape on the twin box, and from Monday morning, the northbound carriageway transformation will also be clear to see.”

Coordinated construction aims to reduce disruption

Balfour Beatty VINCI said carrying out both projects during the same closures would reduce the overall impact on road users.

Oliver Shore, Project Director for Balfour Beatty VINCI, said: “We have specialist teams ready to deliver the next exciting phase of construction over the M42 motorway this weekend. Our engineers will begin the process of extending the Water Orton viaducts over the M42, while a separate team will continue to install the next set of concrete roof beams on top of our twin box structure near Solihull.