HS2’s TBMs are about to start tunnelling towards Euston

The two giant tunnel boring machines that will soon dig the HS2 rail tunnels between Euston and Old Oak Common are now being assembled ahead of tunnelling starting next year.

Rail Minister and new CEO at Old Oak Common station box to see the two TBMs preparing to build HS2 to Euston (c) HS2

The tunnel boring machines (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.

Once they start digging, starting at Old Oak Common, they are expected to take around one and a half years to reach Euston station.

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 announcement about the TBMs comes on the day that Mark Wild joins HS2 as the company’s new chief executive. Mark Wild was the man who took over the Crossrail project when it ran into the ground and led it through to its opening date.

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.”

Once the tunnel to Euston has been dug, the machines will complete their journeys underground, and the outer can of the machine will be left to form part of the tunnel. The mechanical components of the TBMs will be pulled back through the 4.5-mile tunnel and disassembled.

The approach to Euston will be completed by spray concrete lined tunnels which will then transition into three tunnels, which will enable trains to be fed into and from platforms at Euston station.

Sprayed concrete lined tunnel from where Euston TBM Karen will launch to construct HS2’s Euston Tunnel (c) HS2

However, the final plans for the future HS2 terminus station at Euston are still under review.