The HS2 Tunnel Boring Machines Revealed

Today HS2 can proudly reveal the first images of our first two Tunnel Boring Machines (TBMs) set to launch on the project later this year. The TBMs are 170 m in length, each one weighs roughly 2,000 t. When they start they will run non-stop for 3.5 years - only stopping for Christmas and Bank Holidays until the tunnels are complete. The tunnels will go as deep as 80 m below the ground – ensuring communities and countryside above are not impacted by the railway.

The size of the TBM cutterhead which will bore the tunnels is 10.26 m. The internal diameter of the tunnels in which the trains will pass through will be 9.1 m, slightly larger than two London buses stacked on top of one another. The tunnels will be lined with concrete segments that will be 2 x 4 m and weigh on average 8.5 t each. 112,000 of these concrete segments will be required to complete both tunnels.

After completion the first two machines will be disassembled before beginning their long journey to Britain. Once they have arrived on site, each TBM will be reassembled, ready for launch and to begin their life underground. Together the TBMs will spend around three years excavating what will be the longest and deepest tunnels on the project, stretching from just inside the M25, to South Heath in Buckinghamshire.