Crossrail tunnelling to start in less than 100 days as first tunnel boring machine unveiled

Europe’s largest construction project has unveiled the first of eight, 1,000 tonne tunnel boring machines (TBM) that will construct the new Crossrail tunnels under central London.

The 140 metre long, fully assembled tunnel boring machine (TBM) is currently undergoing factory testing. The machine will shortly be dismantled and shipped to London where it will be re-assembled at Westbourne Park ahead of tunnelling commencing from Royal Oak in March.

To construct the 21km of twin-bore tunnel required for Crossrail, eight tunnel boring machines will be required and will undertake ten individual tunnel drives to construct the 6.2m diameter tunnels. At 140 metres, each TBM would just fit just inside the boundaries of a cricket oval.

The TBMs will bore the tunnelled section of the 118 kilometre rail line that will link Maidenhead and Heathrow in the west with Shenfield and Abbey Wood in the east. When completed, Crossrail will bring an extra 1.5 million people within 45 minutes journey of London and reduce cross London journey times.

The TBMs will run 24 hours a day, 7 days a week stopping only for scheduled maintenance.

As the TBMs advance forward, precast concrete segments will be built in rings behind the TBMs. Construction of the concrete segment factory for the western running tunnels between Royal Oak and Farringdon is now complete at Old Oak Common. The plant will begin manufacturing over 70,000 segments for the western tunnels from January.

Chris Dulake, Crossrail’s Chief Engineer said: “Crossrail tunnelling will get underway in March 2012 when the first of eight tunnel boring machines will begin burrowing below the streets of London. Work is continuing across the Crossrail route to prepare for construction of the major new rail tunnels. The new Tunnelling and Underground Construction Academy has welcomed its first students and will train at least 3,500 people with the skills required to work below ground while the first of the tunnel segment manufacturing plants will shortly commence full operations.”

The eight Crossrail TBMs are being manufactured by Herrenknecht AG, Germany who also manufactured tunnel boring machines for the Jubilee Line Extension and the Docklands Light Railway (DLR) Extension to Bank.

Following the launch of the first TBM in March 2012, a second TBM will be launched from Royal Oak a few weeks later. The remaining TBMs will be launched from Limmo Peninsula in the Royal Docks heading towards Farringdon in late 2012; from Pudding Mill Lane and Plumstead in 2013 and from Limmo Peninsula to Victoria Dock in 2014.