Crossrail involves the construction of a tunnel under London connecting
the Great Western Main Line (GWML) at Paddington with the Great Eastern
Main Line at Stratford, with an underground branch from Whitechapel
running under the River Thames to Abbey Wood. The project requires the
excavation of 41km of 6m-diameter single-bore tunnels, the construction
of seven underground stations, and electrification of the Airport
Junction-Maidenhead section of the GWML. Preliminary works began at
Canary Wharf in May, and demolition work is now underway at Tottenham
Court Road, where tunnel boring machines will be launched in 2011.
The line is expected to increase London's overall rail capacity by 10% when it opens in 2017.