Crossrail Limited, a UK company set up to oversee the £17bn ($26bn) Crossrail project, has invited bids for the final stretch of work on the Thames Tunnel.
Work involves two 6m diameter, 2.6km-long tunnels from Plumstead to North Woolwich and includes the construction of sumps for tunnel drainage, cross passages, shafts and portal structures.
The tunnel is part of 21km of tunnelling required for Crossrail. The 118km railway will run from Maidenhead and Heathrow in the west, through central London to Shenfield and Abbey Wood in the east.
Following completion of the project, the railway is expected to carry at least 1,500 passengers in ten-carriage trains through the tunnels, significantly reducing journey times between Heathrow, the West End, the City and Canary Wharf.