Behind the breakthrough | HS2 milestone

This video takes you behind the scenes with the team building HS2’s tunnels. On Thursday 30 March 2023, 2,000 tonne tunnel boring machine ‘Dorothy’ completed the second bore of HS2’s Long Itchington Wood Tunnel in Warwickshire. The milestone breakthrough marked the full completion of first twin bore tunnel on HS2. HS2’s tunnelling team in Warwickshire celebrated the milestone breakthrough of tunnel boring machine ‘Dorothy’ as the giant cutterhead broke through the wall of the Long Itchington Wood Tunnel south portal. Launched in November 2022, it’s only taken four months for the 2,000 tonne TBM to complete its one-mile second bore, making this the first complete twin-bore tunnel on the HS2 project. This marks the culmination of a three-year operation, from site set-up and TBM assembly, the first TBM drive and breakthrough, and now completing the second breakthrough. The tunnelling team have been working around the clock in shifts for four months to operate the TBM, which has put 791 concrete rings in place, with each ring made from eight two-metre-wide segments that each weigh up to 8 tonnes. The tunnel, which preserves the ancient woodland above, forms a key element in how HS2 is managing environmental impacts through the design of the railway, protecting Britain’s precious wildlife habitats. Long Itchington Wood is classified as a Site of Special Scientific Interest (SSSI) with complex ecosystems that have taken hundreds of years to establish.