TBM launch location: aerial view of the South Portal site, with TBM Cecilia in place prior to launch. Florence has already disappeared into the second bore.
COURTESY HS2
Unique machines: ground level view of the South Portal TBM launch site.
PHILIP SHERRATT
Anyone who doubts that HS2 is real and construction is happening need only visit the Chalfont Lane construction site at the South Portal of the Chiltern Tunnels in Buckinghamshire, just inside the M25 motorway. From the largest construction site on HS2, the Align Joint Venture (comprising Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick) is building two of the most significant pieces of infrastructure on thePhase One route from London to the West Midlands – the 16km twin-bore Chiltern tunnels and the 3.4km Colne Valley viaduct.
