The first section of the Metro Tunnel is now complete – with Tunnel Boring Machine Joan breaking through at Kensington to complete the journey between Arden Station and the western tunnel entrance.
For the breakthrough, the team filled the 13-metre shaft with water to maintain pressure and stabilise the ground due to it being so close to the active rail corridor.
Since her launch in August 2019, Joan has travelled 1.2 kilometres and installed 4,200 curved concrete segments to create 700 rings lining the walls of the tunnel. The segments, each weighing 4.5 tonnes, are among 56,000 being manufactured by 70 workers at a purpose-built concrete manufacturing plant in Deer Park.
Watch as Joan enters the flooded retrieval shaft and breaks through the western tunnel entrance.