PREVIEW

Britain’s beleaguered HS2 project marked a major breakthrough on Tuesday (27February2024) when 'Florence,' a 2,000-tonne Tunnel Boring Machine (TBM), completed its nearly three-year, 10 mile journey under the Chilterns.
The 'Florence' TBM, the first of 10 machines assigned to excavate the 32 miles of tunnel for the new railway, commenced its journey in May 2021.
Rail Minister Huw Merriman said: “This ground-breaking moment for HS2 demonstrates significant progress on the country’s largest infrastructure project, with ‘Florence’ paving the way for faster, greener journeys between London and Birmingham while supporting hundreds of jobs and apprenticeships along the way.
“Today’s breakthrough of HS2’s longest tunnel highlights the momentum behind the project and the achievement is testament to the hard work and dedication of the 450-strong team helping deliver the line that will transform rail travel for generations to come.”
The twin-bore Chiltern tunnel, stretching from the South Portal near the M25 to South Heath in Buckinghamshire, was created using two identical TBMs. 'Florence' is the pioneer, with a companion TBM named 'Cecilia' expected to break through in the coming weeks. These TBMs, designed for the Chilterns' unique geology, serve as underground factories, excavating and lining the tunnel with 56,000 pre-cast concrete segments at an average speed of 16 meters per day.
Environmental considerations are behind the decision to tunnel under the Chilterns with the 3 million cubic meters of material removed during tunnelling being repurposed for a grassland restoration project at the south portal. This will encompass 127 hectares of new landscaping, wildlife habitat, and biodiverse chalk grassland, supporting over 40 species per square meter, including some of the UK's rarest orchids and invertebrates.
The tunnel, reaches a depth of 80 meters beneath the Chilterns and passes under the M25, local railway lines, and the River Misbourne twice.

The high speed railway was originally supposed to go to Manchester and Leeds - linking up the North and South of England but will now end at Birmingham due to government cutbacks.