HS2’s ‘green tunnel’ at Wendover in Buckinghamshire took a major step forward this week with the completion of the central part of the cut-and-cover structure which has been designed to cut noise and disturbance for people living nearby.
Set to stretch for around a mile (1.4km), the tunnel is being built inside a cutting alongside the A413 to the west of the town. Once each section is complete, earth is being put back on top to blend the railway into the surrounding countryside.
There are five green tunnels on the HS2 project between London and Birmingham with the Copthall tunnel, on the outskirts of the capital, completed in the summer.
Assembled from 2740 precast concrete segments, the Wendover green tunnel is in an ‘M’ shape, with separate halves for northbound and southbound trains.
To speed up construction, the tunnel was being built in two sections to allow excavation, preparatory work, construction and backfilling to happen at different points simultaneously. These two halves met this week, with the last segment slotted into place on Monday.
To mark the achievement, the team took a moment to sign their names on the segment before it was lifted into position.
With the central part now finished, the focus is turning to the portals at either end, completing the floor slab and internal fitout. Ellesborough Road – which runs from the town in the direction of Princes Risborough – is currently carried over the construction site on a temporary bridge. The final stage will be to realign it over the top of the tunnel and complete the landscaping.
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 built by EKFB, HS2’s main works contractor responsible for the central section of the route through Buckinghamshire and into South Warwickshire. EKFB is a joint venture made up of Eiffage, Kier, Ferrovial Construction and Bam Nuttall.
More than 1.2 million cubic metres of material – mainly chalk – was excavated to form the level base for the tunnel. This was stored on site and is now being carefully backfilled and compressed to ensure that the weight is spread equally across the structure.
Wendover is one of three green tunnels being built by EKFB, with lessons learnt shared between the different teams to help improve productivity and speed up construction.
This includes pre-fabricating, reinforcement cages for the base slab, improving the delivery of concrete through the tunnels and testing to safely increase the size of machinery backfilling the tunnel.
While most of the segments were lifted with a crane, the ones under the Ellesborough Road temporary bridge were lifted into position using a specialised piece of equipment called a self-propelled modular transporter (SPMT).
Supported by 16 sets of wheels, this highly manoeuvrable machine allowed engineers to lift the beams from underneath and place them precisely into position beneath the bridge.
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.”
In total, about 65 miles (105km) of tunnels will be built between London and the West Midlands, and 130 million tonnes of earth will be excavated. Most of these will be deep-bored tunnels, while five will be shallower ‘cut-and-cover’ tunnels like the one at Wendover. These are at Chipping Warden, Greatworth and Burton Green and the Copthall tunnel in Hillingdon.
Once complete, HS2 will improve connections between London, Birmingham and the North while freeing up space for more local trains on the most congested southern end of the existing West Coast Main Line into London Euston.
However, there is still significant work to do across the whole 140 miles between London and Birmingham. Mark Wild, HS2 Ltd Chief Executive, is now leading a comprehensive reset of the project to ensure the remainder of the route is delivered as efficiently as possible and for the lowest reasonable cost.
Image credit: HS2 Ltd
