2,000-tonne Dorothy makes first HS2 tunnel breakthrough

The tunnelling work is part of the in-construction London to Birmingham high-speed railway line.

This section is the first of 64 miles of intricate tunnels that will built as part of Europe’s largest infrastructure project. The 10m-wide machine spent around 8 months underground creating the tunnel, before breaking through at Long Itchington Wood in Warwickshire late last week.

Named after Dorothy Hodgkin, the first British woman to win the Nobel Prize in chemistry in 1964, Dorothy is one of HS2’s 10 custom-built tunnel boring machines and was manufactured in Germany by Herrenknecht. Her operation required around 400 workers, adding to the over 25,000 jobs created through HS2 so far.  

HS2 minister Trudy Harrison said: “This is, quite literally, a ground-breaking moment – demonstrating that we are getting on with delivering on our promises and progressing our transformative plans to boost transport, bring communities together and level up the north and Midlands.

“As Dorothy paves the way for journeys between Birmingham and London, we continue to strive towards a greener, faster and more direct transport network.”

The tunnels have been specially designed to protect the ancient woodland and complex ecosystem above. They integrate with the natural landscape by reusing material excavated from the tunnel to build a soil ‘roof’ around the tunnel entrance. The rest of the excavated material will be transported by conveyor belt out of the site rather than by lorries and trucks in order to avoid the use of around 30,000 HGVs on the local roads.

HS2 will play a key role in the UK’s £96bn Integrated Rail Plan – the biggest ever public investment in Britain’s rail network – which is supposed to add more seats, shorten journey times and support local services through the creation of three new high speed lines.

HS2’s CEO Mark Thurston said: “This is a historic moment for the HS2 project, and I’d like to congratulate everyone involved in delivering it.

“The 400-strong team, including tunnelling engineers, tunnel-boring machine operators and the construction workers at both portal sites, have pulled out all the stops to achieve this fantastic milestone.”

In 2020, HS2 outlined plans to incorporate robotic arms into two tunnel-boring machines that were used to bore the 16km Chiltern Tunnel in order to improve the safety and efficiency of the boring process.