UK: Mayor of London Sadiq Khan announced on January 20 that tunnelling on London Underground’s Northern Line extension to Battersea is to begin in March.

Two tunnel boring machines supplied by NFM Technologies have been unveiled at Battersea and are undergoing final tests. They were shipped from NFM’s factory at Le Creusot in France before being reassembled in London earlier this month. Each 650 tonne TBM can bore up to 30 m per day and requires a team of 50 people to operate. The TBMs have been named Helen and Amy after astronaut Helen Sharman and aviator Amy Johnson.

Excavation of the 5·2 m diameter twin tunnels at a depth of 26 m is expected to take six months and will require nearly 20 000 precast concrete segments to be installed. The tunnelling is expected to create 300 000 tonnes of spoil, with a further 380 000 tonnes coming from the two stations and other parts of the project. Transport for London says that 92% of this will be loaded onto barges and taken along the River Thames to Goshems Farm in East Tilbury in Essex, where it will be used to create arable farmland.

‘Extending the line to Nine Elms and Battersea is going to be a real boost to south London, with the improved transport link helping to provide thousands of homes and jobs for Londoners’, said Khan.

Construction of the 3·3 km extension from Kennington was officially launched on November 23 2015. It is being undertaken by Ferrovial Agroman Laing O’Rourke under a six-year design-build contract awarded in 2014. Completion is due in 2020.

‘The Nine Elms regeneration programme is one of the greatest sources of new jobs and homes in the country and this would not be possible without the Tube link’, said leader of Wandsworth Council Ravi Govindia.

The total project cost is estimated at £1·2bn. £1bn of this is coming from the private sector through a package agreed between the government, Mayor of London, Wandsworth and Lambeth councils, and Battersea Power Station. This includes the creation of a 25-year Enterprise Zone from 2016. The European Investment Bank is providing a £480m long-term loan.

‘This new Tube line paves the way for over 200 ha of former industrial land to be transformed into a place for shops, offices, restaurants, homes and public parkland’, said Battersea Power Station CEO Rob Tincknell.