Northamptonshire HS2: Watch moment last of 5,020 concrete segments of 1.5 mile green tunnel lifted into place

Footage shows the moment the last of 5,020 precast concrete segments was lifted into place at Chipping Warden Green Tunnel last week - marking a major milestone on the HS2 route between London and the West Midlands.

At 1.5 miles (2.5km) long, Chipping Warden is one of the UK's longest cut-and-cover railway tunnels. Built within a cutting and covered with earth, it will reduce noise and visual impact, helping the new railway sit naturally within the Northamptonshire countryside.

HS2 says teams more than doubled their segment installation rate over the course of construction by refining methods, improving logistics and carrying out off-site testing.

Work is now under way on waterproofing, internal floor slabs and emergency walkways, ahead of railway systems installation. Once complete, the tunnel will be landscaped with restored hedgerows, woodland planting and new habitats.

Chipping Warden is one of five green tunnels on the HS2 route. Together, they are designed to reduce environmental impact while supporting a railway that will boost connectivity and free up capacity on the West Coast Main Line for local passenger services and freight.

Sam Arrowsmith, HS2 Ltd’s Senior Project Manager, said: “It’s great to see the final segment slotted into position at Chipping Warden and I’d like to thank everyone who pulled together to find ways to optimise all the stages of construction - from excavation, tunnel construction, and backfilling.

“We’ve still got a long way to go, but with the tunnel precast structure complete, we can now focus on finishing the interior works and the earthworks and landscaping that will blend the railway into the surrounding countryside.”

Chris Barrett, EKFB’s Senior Project Manager, said: “Watching the final tunnel segment being lifted into place is the outcome of 18 months of rewriting the playbook, learning, innovating and putting the right solutions forward when challenged, all of which have boosted on site productively.

“This success has allowed EKFB to safely work at twice the speed compared with the start of construction works in 2023. Now our focus shifts to completing waterproofing and internal works as well as backfilling earth around the tunnel and by the end of winter, it’ll be buried and largely out of sight.

“Thank you to my team, our client HS2, and our supply chain partners for their unwavering dedication and hard work to get to us to this milestone – placing the last remaining segment out of 5,000 is worth a celebration.”