Crossrail pushes ahead with tunnel construction

Two more tunnel boring machines (TBMs) are ready to make the journey to London for the Crossrail project in the UK's captial

Crossrail Limited (CRL), the wholly-owned subsidiary of Transport for London, is preparing to take delivery of its sixth and seventh TBMs to be used on construction of the 118km rail route.

CRL will receive TBM 6, known as Mary, and TBM 7 in late February, after the machines cleared factory testing at the Herrenknecht factory in Germany at the end of January.

Mary will drill a tunnel under the Thames from Plumstead to North Woolwich. 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. 



Mary is named after the wife of the famous 19th century railway engineer Isambard Kingdom Brunel. The TBM weighs 1,000 tonnes and is 110m long. TBM 7 is 150m long. Both have a cutter head diameter of 7.1m.

Once up and running, the TBMs will progress at a rate of 100m a week.

Crossrail’s final tunnel boring machine, TBM 8, will complete factory testing this summer.

With a total funding envelope of £14.8 billion (€17 billion), Crossrail will run from Maidenhead and Heathrow in the west to Shenfield and Abbey Wood in the east, passing below central London. The route will include 21km of new twin-bore tunnels running below central London.

Crossrail services are due to start operating through central London in 2018.

Earlier machines Elizabeth and Victoria started work on the Crossrail project in November last year.