HS2 has reached a significant construction milestone in Buckinghamshire, with the central section of the Wendover Green Tunnel now complete. The achievement marks a major step forward in delivering one of the railway's key environmental mitigation features, designed to reduce noise and visual intrusion for local communities.
Located alongside the A413 to the west of Wendover, the tunnel will extend for approximately 1.4km and is being constructed using a cut-and-cover method. Once completed, the structure will be covered with earth and landscaped to blend into the surrounding Chiltern countryside.
The Wendover Green Tunnel is one of five green tunnels being delivered along the HS2 route between London and the West Midlands. It follows the completion of the Copthall Green Tunnel in west London earlier this year.
Built from 2,740 precast concrete segments, the structure has been designed in an 'M' configuration, creating separate bores for northbound and southbound high-speed services.
To accelerate delivery, the tunnel has been constructed from both ends simultaneously, allowing excavation, ground preparation, installation and backfilling activities to take place in parallel. This week, the two construction fronts met for the first time, with the final central segment installed on Monday.
Members of the construction team marked the occasion by signing the final segment before it was lifted into position.
Attention will now turn to completing the tunnel portals, floor slab installation and internal works. The final phase of construction will also see Ellesborough Road, currently supported by a temporary bridge over the site, permanently realigned across the finished tunnel before landscaping is completed.
HS2 Ltd’s Project Manager, Umesh Gorasia said:
"It’s great to see the two halves of the tunnel linked up for the first time. Once complete, the green tunnel will dramatically reduce disruption from passing trains and blend the railway into the countryside.
“There’s still some way to go, but we’re making good progress and I’d like to thank the team for all their hard work.”
The tunnel is being delivered by EKFB, HS2's main works contractor for the central section of the route through Buckinghamshire and into South Warwickshire. The joint venture comprises Eiffage, Kier, Ferrovial Construction and BAM Nuttall.
More than 1.2 million cubic metres of material, predominantly chalk, was excavated to create the tunnel cutting. The excavated material has been retained on site and is now being reused during a carefully controlled backfilling process designed to ensure an even load distribution across the structure.
Wendover is one of three green tunnels being constructed by EKFB. Lessons learned from the programme have been shared across project teams, helping to improve productivity, construction methods and delivery timescales.
Innovations introduced include the prefabrication of reinforcement cages for the base slab, enhanced concrete delivery methods and trials to safely increase the size of machinery used during the backfilling process.
While most of the tunnel segments were installed using conventional cranes, engineers adopted a different approach beneath the temporary Ellesborough Road bridge. Here, segments were lifted using a self-propelled modular transporter (SPMT), a highly manoeuvrable specialist vehicle supported by 16 sets of wheels. The machine enabled engineers to precisely position segments beneath the restricted working area.
EKFB’s Project Manager, Elton Qafaliaj said:
"EKFB installed the first concrete segment in spring 2025, and in less than 18 months, we have lifted more than 2,000 segments to complete the central structure of the Wendover green tunnel. This was a huge undertaking and has required the expertise of a skilled workforce. The team has worked together to safely overcome challenges, keeping productivity high and pushing the construction programme forward.
“Seeing the two halves of tunnel finally come together was a proud moment for everyone involved.”
HS2's wider programme includes around 105km of tunnels between London and the West Midlands, with five of these constructed using the cut-and-cover method. Alongside Wendover, green tunnels are being delivered at Chipping Warden, Greatworth, Burton Green and Copthall.
Once operational, HS2 will provide faster journeys between London, Birmingham and the North, while releasing capacity on the heavily congested southern section of the West Coast Main Line for additional local and freight services.
Significant work remains across the 140-mile railway between London and Birmingham, with HS2 Chief Executive Mark Wild continuing to lead a programme-wide reset aimed at improving delivery efficiency and achieving the lowest reasonable cost.
Image & Video credits: HS2
