National Highways has chosen the German company Herrenknecht to build the largest tunnel boring machine ever used in Europe for the Lower Thames Crossing.
The company has previously made the machines used to create the Elizabeth Line, the Silvertown Tunnel, HS2 and the Thames Tideway tunnels.
The new machine is expected to be bought and operated by the project's Delivery Partner, Bouygues TP Murphy Joint Venture.
National Highways has declined to state how much the tunnel borer will cost. When approached by Highways, National Highways stated that the value was 'commercially sensitive but is contained within the overall budget for the tunnel contract'.
Purchase prices listed for the machines that were used during construction of the Elizabeth Line and HS2 come to between £15m and £20m per machine.
The 120-metre-long, 5,000-tonne machine will be delivered to the site in segments and is expected to begin work in 2028. National Highways stated that this is on track with the expected opening of the crossing in the early to mid-2030s.
Its 16.4-metre diameter will make the machine the largest ever used in Europe, and the third largest ever in the world. The machine's size dictates that it be delivered to the site in segments by sea and carried up the Thames and delivered to the Port of Tilbury.
It will dig two parallel 2.6-mile-long tunnels, each more than twice the size of the existing tunnels at Dartford and big enough for three lanes of 70mph traffic. This makes the project the longest road tunnel in the UK.
National Highways also plans to power the machine with electricity from renewable sources.
One machine will be used to dig both tunnels, with tunnelling expected to begin near the Port of Tilbury in 2028 before turning around and completing the second bore.
Shaun Pidcock, delivery director for Lower Thames Crossing, said: ‘Choosing our partner to supply the giant tunnel boring machine means real progress on the project – and we'll put it to work as soon as it arrives on site in 2028.'
Didier Jacques, tunnel construction director at Bouygues Travaux Publics Murphy Joint Venture, said: ‘In close collaboration with Herrenknecht, the team will now work on the detailed design development of the tunnel boring machine. Our focus remains steadfast: working at pace to reduce carbon emissions, pioneer innovative solutions and embed safety at every stage of construction.'
Frédéric Battistoni, head of project management at Herrenknecht, said: ‘The Lower Thames Crossing Tunnel Boring Machine will be the largest machine ever built at Herrenknecht's headquarters in Germany and the largest Variable Density TBM ever. It will also be equipped with the largest accessible cutting wheel ever built by Herrenknecht. Incorporating several industry-first innovations, the machine has been designed to adapt to changing ground conditions while enhancing safety, efficiency and logistics during tunnelling operations. The machine will support the excavation of both tunnel drives through a planned U-turn configuration.'
National Highways has been approached about the value of the machine.
