HS2 has launched its third tunnel boring machine (TBM), which will drill 3.4 miles under London.
The TBM, known as Emily, will cover the route between the Victoria Road Crossover Box, near Old Oak Common, to Greenpark Way in Greenford.
Emily is the third of four TBMs launched to construct the twin-bore Northolt Tunnel, which will span 8.4 miles when complete.
The joint venture between Skanska, Costain and Strabag (SCS JV), which is the contractor on HS2’s London tunnels section, constructed the TBM underground after lowering parts into the shaft.
The TBM was manufactured by Herrenknecht in Germany and weighs 1,700 tonnes. Its cutterhead has a diameter of 9.11 metres.
HS2 Ltd project client director Malcolm Codling said HS2 was working at “peak construction”.
“The preparation to launch TBM Emily has been complex and we remain on schedule to complete the Northolt Tunnel in 2025,” he added.
Emily is named after Emily Sophia Taylor, who became Ealing’s first female mayor in 1938. She also helped to establish the Perivale Maternity Hospital in 1937.
HS2 will transport all the clay extracted from the tunnel to Cambridgeshire, Kent and Rugby, where it will be reused at other sites.
HS2 trains will travel from Old Oak Common to West Ruislip, with Emily and fellow TBM Anne building nearly half of the tunnel. Anne will be launched next month.
TBMs Sushila and Caroline are constructing the eastward part of the tunnel from West Ruislip to Greenford. HS2 expects the TBMs to finish boring the Northolt Tunnel in 2025, when they will be lifted from the ground through giant shafts at Greenpark Way.
Later this year, HS2 expects to deliver another two TBMs to Old Oak Common, which will start boring the tunnel to Euston.
Currently, the funding and delivery arrangements for the Euston tunnel are being reviewed, after HS2 was stripped of the management of the Euston station project last year. The station will be privately funded.
