Crossrail celebrates sixes and sevens

Crossrail’s sixth and seventh tunnel boring machines (TBMs) have rolled off the production line and are set to start their journey to London.

Both machines have recently completed factory testing at the Herrenknecht factory in Germany and will be shipped through Rotterdam and transferred by ship to Tilbury in Essex.

TBM 6, Mary, will drill a tunnel under the Thames from Plumstead to North Woolwich alongside her sister machine, Sophia, who commenced tunnelling at the start of January. Known as a ‘slurry’ machine, Mary is specially equipped to deal with the chalk, flint and wet ground conditions that she will encounter in southeast London.

TBM 7 will be used on the drive from Pudding Mill Lane to Stepney Green, which will start in the summer. This is an Earth Pressure Balanced machine designed for the London clay found north of the River. All the machines’ components are expected to arrive at Crossrail’s sites within the next month where they will be reassembled. There are no manufacturers of tunnel boring machines in the UK.

Says Andy Mitchell, Crossrail Programme Director, ‘Over 4km of tunnel has now been constructed on Crossrail. With tunnelling now well underway we are looking forward to welcoming our sixth and seventh tunnel boring machines to the project. Once we’ve unpacked and reassembled them, they’ll begin drilling yet more tunnels underneath the streets of the capital.’