HS2 has launched its third giant tunnel boring machine (TBM) in London that will construct the Northolt Tunnel.
TBM Emily will dig 3.4 miles of the 8.4-mile Northolt Tunnel. The 1,700-tonne machine will travel under Ealing from the Victoria Road Crossover Box to Greenpark Way in Greenford.
TBM Emily was manufactured by Herrenknecht in Germany. As an earth pressure balance machine, it is designed specifically for the soft London clay that will be extracted from the ground.
HS2’s London Tunnels contractor, Skanska Costain STRABAG joint venture assembled the TBM underground at the Victoria Road site, near the new Old Oak Common station.
“We are working at peak construction on HS2, delivering the tunnels which HS2 trains will travel through under London. The preparation to launch TBM Emily has been complex and we remain on schedule to complete the Northolt Tunnel in 2025.”
The Northolt Tunnel will allow HS2 trains to travel in and out of London from Old Oak Common to the outskirts of the capital at West Ruislip.
The twin-bore tunnel is being built in two sections. TBMs Sushila and Caroline are constructing it eastbound between West Ruislip and Greenford, while TBMs Emily and Anne will dig the tunnel from the Victoria Road Crossover Box to Greenford. TBM Anne will be launched next month as the fourth and final Northolt TBM.
The four TBMs are scheduled to complete their journeys in 2025, when they will be extracted at Greenpark Way.
The London Clay that will be extracted by the TBMs will be transported by rail to be reused at sites in Cambridgeshire, Kent and Rugby.
“The HS2 London Tunnels team are well on the way to delivering a new railway into the heart of London with the launch of TBM Emily. Next month, we will be launching TBM Anne who together with Emily will form the tunnel from Old Oak Common to Greenpark Way Shaft where they will meet with TBMs Sushila and Caroline, who are already halfway to completing their journeys from West Ruislip.”
