Two factories are producing 196 pre-cast concrete segments a day to line the 16km twin-bored tunnel running under the Chilterns.
Align, a joint venture between Bouygues, Sir Robert McAlpine, and VolkerFitzpatrick, is delivering the Central 1 (C1) package of HS2 Phase 1 that consists of 21.6km of high speed rail infrastructure, including the tunnel and a 3.37km viaduct across the Colne Valley.
The factories at the south portal of the tunnel produce the segments before they are transported by two giant gantry trains.
The first of the tunnel boring machines to be used to excavate the tunnels, called Florence, was launched at the site in May this year.
In total, 112,000 individual segments will be produced to line the tunnels.