By rosebell
In order to excavating the 7.5km-long Euston Tunnel that is due to carry HS2 trains into the heart of London, engineers have commenced assembling the two TBMs.
The location of commissioning these Herrenknecht TBMs is an underground box at one end of the project’s Old Oak Common station and they are expected to take almost one-and-a-half years to reach the railway’s southern terminus at London Euston, whereas the number of TBMs used for the deep bored sections of the 225km route between London and the West Midlands will take to 10.
With 1,250 tonnes weight and 190m length, the TBMs were lifted into the underground station box through a 750-tonne crane over the summer and currently they are being reassembled at the eastern end of the station, ready to bore to Euston.
Being optimised for London clay, the cutterhead of the machine has an 8.53m diameter, and the inner diameter of the tunnel will be 7.55m, while their average advance will be 16m per day.
Considering that the approach to Euston is slated to be completed by sprayed concrete lined tunnels which will then transition into three tunnels, which is going to enable trains to be fed into and from platforms at Euston station, one of the machine’s has been named Karen after Karen Harrison (1960-2011), the first female train driver in the UK, who was based out of Old Oak Common depot. The other is named Madeleine, after Madeleine Nobbs (1914-1970), a former president of the Women’s Engineering Society.
The date of unveiling of the final TBMs for the high-speed railway was on the day that Mark Wild took over as HS2 Ltd’s new chief executive, and he as the former CEO of Crossrail, will help oversee the project’s transition from a major construction programme to a working railway, with a renewed focus on controlling costs.
Rail minister Lord Hendy welcomed Mark Wild to HS2 and said: “The sheer scale of the progress at Old Oak Common – and the benefits we will realise from taking HS2 to Euston, as confirmed in the Budget – reminds us that this is a once-in-a-generation project. HS2 will not only improve transport links for millions but unlock huge potential for growth, jobs and regeneration right across the country.”
“It was exciting that the TBMs would be launched soon. After so much uncertainty, it’s great to finally be working with a government that recognises the huge importance of this scheme to London and the UK, and understands why terminating HS2 at Euston is so important,” said the Mayor of London, Sadiq Khan.
In October 2024 the government gave the green light for the tunnel between Old Oak Common and London Euston in the Budget.
As a leading construction of the twin-bored tunnel,HS2’s London tunnels contractor, Skanksa Costain Strabag (SCS) joint venture completed the 853m-long Atlas Road Logistics Tunnel in January this year, which is due to provide access for materials, and a route to remove the excavated London clay. It has also constructed two spray concrete-lined tunnels from which the TBMs will be started up eastwards towards Euston, while the expected date for commencing the excavation process is 2025.
SCS is already well advanced with construction the Northolt tunnel, a separate structure running west out of Old Oak Common towards West Ruislip.
SCS managing director James Richardson said: “The joint venture was delighted the government had given the green light to delivering HS2 through to Euston. Over the past two years, we have continued with critical activities to ensure that we can deliver the Euston Tunnel and approaches quickly, and at the lowest possible cost,” he said. “We are also making excellent progress on the tunnelling between West Ruislip and Old Oak Common, with four TBMs in operation, and the works well over 50% complete.”
Considering that the HS2 Ltd is continuing to work with the government and other stakeholders to an affordable station design, the final plans for HS2’s terminus station at Euston are still under review and further details will be announced by the government in due course.
