Florence and Cecilia, the two tunnel boring machines being operated by Align on the C1 portion of HS2, reached their milestone: Chalfont St Peter ventilation shaft. The 78 metre deep shaft is the first of five that will provide ventilation and emergency access to the twin tunnels. 

This marks an important step for the project with a combined 5,7 kilometres of tunnels already dug by the two giant machines, each weighing 2,000 tonnes, since their launch last summer. Designed specifically for the mix of chalk and flint under the Chilterns hills, these 170 metre long self-contained underground factories have made significant progress on the first stage of their journey.

Each tunnel will be lined with rings of concrete segments, 56,000 are required for each tunnel, made in two precast factories located at Align’s South Portal site to the West of London just inside the M25 motorway. During this first stage of their journey, Florence and Cecilia have combined installed more than 20,000 separate segments, each weighing around 8.5 tonnes.

Congratulations to Align’s teams!