SCS JV begin works on HS2 tunnel between Old Oak Common and London Euston
Our Skanska Costain STRABAG joint venture (SCS JV) engineers have begun assembling two giant tunnelling machines that will dig the final 4.5 miles of underground high-speed railway – carrying HS2 trains into the heart of London. This follows the Chancellor of the Exchequer, Rachel Reeves funding commitment for the final part of the HS2 London tunnelling contract.
Weighing an incredible 1,250 tonnes, each of the tunnel boring machines (TBMs) will launch from an underground box at one end of the project’s Old Oak Common station. They are expected to take around a year and a half to reach the railway’s final southern terminus at London Euston.
As well as taking passengers closer to central London, the extension to Euston will create additional capacity on the new high-speed line, allowing more services to run to a greater number of destinations across the Midlands and the North.
Arrival of the line into Euston is also expected to trigger a transport-led regeneration of the area – unlocking opportunities for thousands of new homes and jobs.
In keeping with tradition, the TBMs have been given female names after prominent women in history. One machine is called Karen after Karen Harrison, the first female train driver in the UK who was based out of Old Oak Common depot. The second is named Madeleine, after Madeleine Nobbs, the former president of the Women’s Engineering Society.
The unveiling of the TBMs – the final set to be launched for the railway between London and the West Midlands – marks another significant milestone for HS2.
It comes on the day that Mark Wild joins HS2 Ltd as the company’s new chief executive. Mr Wild, 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 said: “I’m delighted to welcome Mark Wild to HS2 and look forward to working with him to successfully deliver Britain’s largest rail project sensibly and efficiently for the benefit of passengers and taxpayers.
“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.”
The two 190m-long TBMs were manufactured by world-leading tunnelling experts Herrenknecht AG in Germany and were transported to Old Oak Common in pieces before being reassembled on site. This summer, the HS2 team lifted the machines into the underground station box using a 750-tonne crane. They are now being reassembled at the eastern end of the station, ready to bore to Euston.
The cutterhead of the machine, which has been optimised to cut through London clay, is 8.53m across with the inner diameter of the tunnel set to be 7.55m.
The TBMs are like underground factories, excavating the tunnels using a turning cutterhead, lining them with pre-cast concrete tunnel segments, grouting them into place before moving forward at an average speed of 16 metres per day. Teams work around the clock below ground on the along with teams on the surface supporting them.
Our SCS joint venture, is leading construction of the twin-bored tunnel. In January 2024 the team completed a logistics tunnel from a nearby site at Atlas Road which will provide access for materials, and a route to remove the London Clay being excavated by the machine. It has also built two spray concrete-lined tunnels from which the TBMs will be launched eastwards towards Euston. Boring is expected to begin in 2025.
Construction the Northolt tunnel – a separate structure running west out of Old Oak Common towards West Ruislip, outer London is already well underway.
James Richardson, Managing Director, SCS JV, said: “We are delighted that the Government has given the green light to deliver HS2 through to Euston, ensuring the full benefits of the new railway are realised. 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.
“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.”