HS2 tunnelling machines reach Chalfont St Peter ventilation shaft
Two enormous Tunnel Boring Machines (TBMs) excavating HS2’s longest tunnels have completed the first stage of their drive – from the Chiltern tunnel’s south portal to the first ventilation shaft at Chalfont St Peter. HS2 this week confirmed that the two enormous 2,000 tonne tunnelling machines digging the high speed rail project’s tunnels under the […]