HS2’s tunnelling operation in London has made a major step forward with the breakthrough of tunnel boring machine (TBM) Emily, completing a 3.4-mile leg of the Northolt Tunnel in Greenford.
The TBM, named after Emily Sophia Taylor – who helped found Perivale Maternity Hospital in 1937 and became Ealing’s first female mayor in 1919 – emerged at Green Park Way after launching from Victoria Road in North Acton in February 2024. In that time, it has excavated 775,000 tonnes of London Clay and installed over 17,500 concrete tunnel segments.
Emily is the third of four TBMs working on the 8.4-mile Northolt Tunnel – a key stretch of the HS2 line connecting outer West London to the new Old Oak Common station. The tunnel is being built in two sections: from West Ruislip to Greenford in the west, and North Acton to Greenford in the east.
Due to challenging ground conditions, including high water pressure, TBM Emily completed its drive into a pressurised “reception can,” allowing safe depressurisation and retrieval of the machine. Manufactured by German firm Herrenknecht, the 1,700-tonne TBM was manned around the clock by crews from the Skanska Costain STRABAG joint venture.
Malcolm Codling, project client director for HS2 Ltd, said: “HS2’s tunnelling drives in London for the Northolt Tunnel are nearing completion and it is a real achievement for our team to complete this 3.4-mile section on the tunnel safely and with such efficiency.”
He added: “There is still much more to do in the tunnel to get it HS2 ready and we will be focusing on productivity to continue with our work safely to get the HS2 route in London ready for track to be laid, and systems installed.”
 Emily, completing a 3.4-mile leg of the Northolt Tunnel in Greenford.){kind=link}