HS2 cutterhead in position to bore second tunnel

The 160-tonne cutterhead for Tunnel Boring Machine Dorothy makes its way through Ufton on September 21. It was moved by a 12-metre-long 48-wheel self-propelled trailer on a 2½-mile journey from the south portal site of HS2’s Long Itchington Wood Tunnel to its northern portal. Having completed HS2’s first tunnel breakthrough in July, the TBM will embark on its second parallel tunnel bore later this year. Most of the 120-metre-long TBM was pulled back through the existing one-mile tunnel by a special

‘caterpillar’ system, at a pace of 150 metres a day. But the ten-metre diameter cutterhead and eight other large pieces from the

TBM’s front and middle shields had to make the 180-minute journey above ground and by road.HS2.