The London Power Tunnels project is the largest single tunnelling contract let to date in the UK. The contract is an integral part of National Grids investment in an electrical superhighway under London. It involves construction of 32 kilometres of 4.0mID and 3.0mID tunnels, 14 shafts, and four connecting tunnels with associated underground chambers.
The tunnels have been driven by a 4.0mID Herrenknecht earth pressure balance TBM and a 3.0mID a Caterpillar MP139SE dual mode TBM from Canada, named Cleopatra and Evelyn by local schoolchildren.
Tunnel Boring Machine (TBM) Evelyn was responsible for constructing 19km of the 32km. In constructing the 32km of tunnel, a total of 151,026 segments or 25,171 rings have been installed.
Overall completion of the project (following commissioning) is planned in 2018.