Giant TBM Sets Off Beneath London in Major HS2 Milestone

HS2 has begun its physical push towards central London, with one of two enormous tunnel boring machines starting work on the Euston Tunnel in a landmark moment for the project.

The 1,624-tonne machine was powered up at Old Oak Common in west London, marking the start of a 4.5-mile journey beneath the capital to Euston. The launch was carried out by Rail Minister Lord Peter Hendy alongside the Chief Secretary to the Prime Minister, Darren Jones, and represents a major step towards bringing high-speed trains into a new central London terminus.

Driving the Euston Tunnel is a key phase of HS2’s wider programme and is seen as critical not only to the railway itself but to the regeneration of the surrounding area. The tunnel will ultimately allow high-speed services to reach a redeveloped Euston station, unlocking investment, housing development and employment opportunities across the district.

The start of tunnelling comes as HS2 undergoes a major programme reset, aimed at placing construction in the correct sequence while providing greater clarity over costs and delivery timelines. The reset is being led by HS2 Ltd chief executive Mark Wild and is intended to stabilise the programme and enable the railway’s long-term benefits, including increased rail capacity and economic growth, to be realised.

HS2 is due to open in stages, with the first services planned between Old Oak Common and Birmingham Curzon Street. Trains will run through to Euston at a later date, a milestone which HS2 says is essential to delivering the full benefits of the new line.

Responsibility for the new HS2 station at Euston will sit with a dedicated Euston Delivery Company. Once established, it will oversee the creation of an integrated transport hub, covering the HS2 station, the redevelopment of the existing National Rail station, upgrades to the London Underground, and wider commercial development across the Euston site.

Research commissioned by Camden Council in 2024 into a locally led regeneration of Euston suggested the scheme could add £41 billion to the UK economy by 2053 and support 34,000 jobs.

The tunnel boring machine was built by Herrenknecht AG in Germany and transported to the UK in 2024 before being lowered into the vast underground station box at Old Oak Common and reassembled. Over the past year, engineers from HS2’s London tunnels contractor, the Skanska Costain STRABAG joint venture (SCS JV), have been preparing the machines for their work.

Operating as a moving underground factory, the TBM will work continuously to excavate the tunnel, install concrete lining segments and grout them into position, advancing at an average rate of around 16 metres a day.

Its progress is supported by the Atlas Road Logistics Tunnel, completed in January 2024. This 853-metre tunnel provides access for construction teams, allows delivery of 48,294 concrete ring segments across the two machines, and enables the removal of more than 1.5 million tonnes of excavated material.

Spoil from the tunnelling will be conveyed to the London Logistics Hub at Willesden Euro Terminal depot, before being transported by rail for reuse on projects in Kent, Cambridgeshire and Warwickshire.

As it heads towards Euston, the machine will pass beneath Kensal Green cemetery, close to the final resting place of Isambard Kingdom Brunel, a pioneering engineer whose work helped define the modern railway.

In keeping with tradition, the TBM has been named after a woman. The first machine to set off towards Euston is called Madeleine, honouring Madeleine Nobbs, a former president of the Women’s Engineering Society. Born in 1914, Nobbs worked as a building services engineer after overcoming family resistance to her chosen career, following encouragement from Adria Buchanan, the first woman member of the Institute of Heating and Ventilating Engineers.

Completion of the Euston Tunnel will mark the end of 27.5 miles of deep-bore tunnelling between London and Birmingham. Of that total, 23 miles have already been finished, with the final machine on the Bromford Tunnel completing its drive in October last year.

Rail Minister, Lord Hendy, said:

“It was brilliant to switch on the tunnel boring machine at Old Oak Common today – not just because it’s an engineering marvel – but because it brings HS2’s journey to Euston another step closer to reality. We’re putting HS2 back on track, and taking the railway into central London is crucial to unlocking its full potential to deliver more jobs, more homes, and a long-term boost to the whole British economy.”

Chief Secretary to the Prime Minister, Darren Jones, said:

“There’s nothing boring about tunnel boring. Today’s launch was a brilliant moment for the UK’s railways, building on six major rail tunnel and road milestones completed ahead of schedule last year. We're boosting the links between our big cities across the country to create more opportunities for people to trade, meet and socialise with each other, turning the corner on years of decline.”­

HS2 Ltd CEO Mark Wild said:

“On my first day at HS2, I unveiled the Euston TBMs as they were being prepared to build the Euston Tunnel. Just over a year on, we’re beginning to excavate the tunnel - a show of confidence that HS2 will be built into central London and kickstart economic growth. Over the past 12months, I have been leading a comprehensive reset across HS2 to get it back on track and I am confident that we’re on the right path to delivering HS2 safely and efficiently. The start of tunnelling here today is a part of the strong foundations we can build upon to completing HS2 and deliver better journeys for rail passengers.”

The Leader of Camden Council, Cllr Richard Olszewski, said:

“Euston holds a once-in-a-century opportunity to boost the national economy, build much-needed affordable homes, and create new jobs for people in Camden and beyond. The start of tunnelling brings us a step closer to that future, adding new momentum and even-greater confidence in Euston’s potential to be a driver of national growth. In Camden we stand ready to lead the next chapter of Euston’s vibrant history through a new, locally led development corporation - working with the GLA and Government to make Euston a place that delivers for the country, the capital and our communities.”

Richard Adams, Managing Director of Skanska Costain STRABAG joint venture said:

“We are delighted to be commencing our final TBM drives to build the two 4.5 mile tunnels to Euston. During this work our TBMs will remove over 1.5 million tonnes of excavated material and place more than 8,000 pre-cast rings, built in a dedicated facility in Hartlepool. Our tunnel segments and excavated material will all be transported by rail and managed through our state of the art logistics hub. This will remove over 70,000 lorry journeys the local road network, emphasising our commitment to being a good neighbour and greener construction. SCS JV has already driven 8.4 miles of twin bore tunnels under London, from West Ruislip to Old Oak Common, and our expert teams on site will work 24/7 to deliver these final HS2 tunnel drives with the highest levels of safety and productivity.”

Image: HS2