Behind the breakthrough: HS2 milestone marks full completion of first twin bore tunnel

This video takes you behind the scenes with the team building HS2's tunnels.

On Thursday 30 March 2023, 2,000 tonne tunnel boring machine ‘Dorothy’ completed the second bore of HS2's Long Itchington Wood Tunnel in Warwickshire. The milestone breakthrough marked the full completion of first twin bore tunnel on HS2.

HS2’s tunnelling team in Warwickshire celebrated the milestone breakthrough of tunnel boring machine ‘Dorothy’ as the giant cutterhead broke through the wall of the Long Itchington Wood Tunnel south portal.

Launched in November 2022, it’s only taken four months for the 2,000 tonne TBM to complete its one-mile second bore, making this the first complete twin-bore tunnel on the HS2 project.

This marks the culmination of a three-year operation, from site set-up and TBM assembly, the first TBM drive and breakthrough, and now completing the second breakthrough.

The tunnelling team have been working around the clock in shifts for four months to operate the TBM, which has put 791 concrete rings in place, with each ring made from eight two-metre-wide segments that each weigh up to 8 tonnes.

The tunnel, which preserves the ancient woodland above, forms a key element in how HS2 is managing environmental impacts through the design of the railway, protecting Britain’s precious wildlife habitats. Long Itchington Wood is classified as a Site of Special Scientific Interest (SSSI) with complex ecosystems that have taken hundreds of years to establish.

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[DavidSmith-]

A tunnel digging project manager called

[chish]

How can anyone not be totally impressed with this achievement? Just quality tunnel engineering.

[joshdushulovci]

I’m doing an apprenticeship for Danny Sullivan group and I am so proud to be part of the hs2 tunnelling team

[rvnadim]

Congratulations on reaching this incredible milestone! It's amazing to see the hard work and dedication that has gone into this project. It's a great reminder of the huge potential of engineering and the power of collaboration. Well done!

[mikehindson-evans]

Great to see the progress. Looking forward to seeing the full video after it launches later this afternoon. Thanks for the great communications aspect of your programme.

[owensmith]

I hope a lot of the team are going with the TBM to Bromford so the knowledge will continue to be useful and the tunnel boring faster.

[davekirk]

Wondered when they were going to start the Bromford tunnel, now I know. Used to live there many many years ago

[peterforan]

Impressive engineering and project execution.

[davedave]

I can never understand how the machine navigates to come out exactly where intended. It can't be GPS because signals blocked so what reference is used? A short video would be great or a link reference if already explained somewhere.

[kwv]

In Brisbane rather than build high speed rail to The Gold and Sunshine Coast, The LNP at previous state level decided to build congestion increasing road tunnels and now at Brisbane Council level decided to build a amusement park ride the Metro.

[EdgyNumber]

Why are we not exporting these skills and services?

[worldcomicsreview]

I'll never live on censorship island again, but it's nice to see it can do a few things right.

[davidhall]

Great video series, detailing the construction of the worlds largest cycle path (which it will be when HS2 gets cancelled).

[martingoffin]

United Kingdom Of Great Britain London and all UK city's are the best in the world, UK HS2 Trains Railways is the best world class, UK Railways business boost business forever. The first railroad built in Great Britain to use steam locomotives was the Stockton and Darlington, opened in 1825. It used a steam locomotive built by George Stephenson and was practical only for hauling minerals. The Liverpool and Manchester Railway, which opened in 1830, was the first modern railroad.

[sandrabennett]

Wonderful sad to see h s 2 will be put on hold l am said about lt x

[hopidenisova]

Mmmyeah and now they have decided to stop digging....
Haha

[chrisroberts]

Great as an engineering achievement it may be touted as, the project as a whole is still a complete waste of money. The same invested into the current infrastructure to get current lines faster and operating reliably would make a huge difference. No one needs to get to Birmingham 20 mins faster or Manchester in half the current time than you can already from London. what would be good is not being left stuck unable to travel or delayed by hours at a time on a regular basis.

[timstarkey-smith]

I m struggling to understand what the French guy is saying, he is talking too fast

[chairmakerPete]

It's a real shame the HS2 project is such a dud, because the engineering is truly amazing.

[TimDyer-febn]

Great engineering, fantastic, but has ruined our countryside, waste of money, no one wants it around that southam area, and further