HS2 launches third TBM in London

The tunnel will be used to deliver materials and remove spoil from the northern portal where HS2’s Euston twin-bored tunnel will be constructed.

SCS JV launched the 847-tonne machine – named Lydia – from the Atlas Road site in North Acton, from where it will build an 853m tunnel to the Old Oak Common Station site. It will start 5m below ground and reach a depth of 20m.

The tunnel drive will be completed in around six months, with the tunnel constructed using 4,264 concrete segments forming 533 tunnel rings. The segments, each weighing over 3 tonnes, have been produced by Pacadar in Kent.

The tunnel will be used to transport 8,010 tunnel segment rings to construct the Euston tunnel. The segment rings are being manufactured by Strabag in Hartlepool and will be transported by rail and the logistics tunnel, rather than by road.

A conveyor will also run through the logistics tunnel. It will connect to an existing conveyor at Atlas Road, taking the London clay being excavated to construct the Euston Tunnel to HS2 London Logistics Hub at Willesden Euro Terminal. From there, the spoil will be taken by train for reuse at sites in Kent, Cambridgeshire and Rugby.

Malcolm Codling, HS2’s project client for the London tunnels, said the Atlas Road Logistics Tunnel was key to constructing the Euston Tunnel between Old Oak Common and HS2’s Euston station.

“The logistics tunnel allows us to take 70,000 lorry journeys off the local roads that would otherwise have been required and will reduce the impact of HS2’s construction on the local community,” he said.

The Herrenknecht TBM has been repurposed using components from a TBM previously used on Crossrail. TBM Ellie dug two sections of the Crossrail tunnels in London – from Limmo Peninsula in Canning Town to Royal Victoria Dock, and between Pudding Mill Lane and Stepney Green – boring a total of 3.58km.

Herrenknecht designed the TBM specifically for HS2’s requirements and remanufactured components, including the shield and the cutting wheel.

Later this year SCS JV will have five TBMs operating on HS2, four of them boring the HS2 tunnels, linking West Ruislip and Old Common.

In March the government announced it was delaying some aspects of the high-speed railway for two years. It said it was committed to HS2 trains eventually terminating at Euston Station in central London, but for now it was prioritising the service between Old Oak Common in west London and Birmingham.