650 tonne Northern Line Extension tunnel boring machines unveiled

Two new 650 tonne tunnel boring machines (TBMs) have been unveiled ahead of work to build the Northern Line Extension tunnels under south London.

The two TBMs, built by NFM Technologies in Le Creusot in central France, will now undergo special factory testing. Once complete, the boring machines will be dismantled and shipped to London later this year. Reassembly will occur in Battersea taking an estimated three months to complete.

“This is the first glimpse of the powerful machines that will help build the Northern Line Extension”

Once in operation, the tunnel boring machines will run 24 hours a day, seven days a week on the 3.2km twin-bore tunnel. As they advance forward, nearly 20,000 pre-cast concrete segments will be built in rings behind them.

Tunnelling for the Northern Line Extension, which will extend the line from Kennington to Battersea via Nine Elms, is due to begin in early 2017 and will take six months to complete. Two new stations will be built: one at the heart of the Battersea Power Station redevelopment and another at Nine Elms to the east, serving new developments such as the US Embassy and the redevelopment of New Covent Garden Market, as well as existing communities.

In total 300,000 tonnes of earth is expected to be excavated and pass along nine conveyors before being loaded on to barges and taken to Goshems Farm in East Tilbury, Essex. The spoil will be used to raise former landfill sites to create arable farmland.

First major extension of the Tube in nearly 30 years

The Mayor of London, Boris Johnson MP, said: “The construction of these mammoth machines is the clearest indicator yet that we are about to deliver the first major extension of the Tube in nearly 30 years. By extending the Northern Line we are improving access to the Tube for thousands of south Londoners as well as triggering the creation of vital new homes and jobs.”

Nick Brown, Managing Director of London Underground, said: “This is the first glimpse of the powerful machines that will help build the Northern Line Extension and bring Battersea and surrounding areas to within 15 minutes of the West End and City. The TBMs will make their way to London later this year and in early 2017 will start powering their way under south London to create the first major Tube extension since the Jubilee line in the late 1990s. Their manufacture is a significant step forward in the project which, once complete, will help us to support jobs, homes and growth in this area and keep pace with London’s rapidly rising population.”

The Northern Line Extension is targeted for completion in 2020.