TBM breakthrough

Engineering services firm Costain and its partners have completed tunnel work on the first of three drives at the London Power Tunnels project for National Grid, using a Lovat tunnel boring machine (TBM).

Costain said that the dual mode TBM, named Evelyn, broke through a pre-prepared shaft at St John’s Wood in London, following a year-long 7.26km drive from Willesden.

The drive is part the National Grid’s plan to rewire London via a 32km network of underground tunnels, in order to meet increasing electricity demand, and help the capital access the renewable energy of the future.

Costain project manager Andrew Firth said; "The best single shift advance was greater than 50m in 12 hours. The machine performed very well."

Evelyn will now be lifted out of the St John’s Wood shaft and transported by road to Wandsworth to start a 3.5km tunnel drive towards Wimbledon.

In six month’s time, the TBM will be transported by road back to Wandsworth, from where it will set out on its final 9km drive to Kensal Green.

The remaining 13km tunnel will be dug by another TBM, named Cleopatra, which is currently operating in Tottenham, north London.


Image: The dual mode TBM, named Evelyn, broke through a pre-prepared shaft at St John’s Wood in London. Photo: Courtesy of Costain.

Energy