Engineers on Channel Tunnel Rail Link Contract 320 last week completed 1km of tunnelling beneath the Thames. Main contractor Hochtief Murphy Joint Venture started digging the 2.5km tunnel from Swanscombe to Purfleet in July.
When the project is completed in 2007, the twin bored tunnel will allow high speed trains to pass under the river. The 1100t, 85m long pressurised slurry tunnel boring machine (TBM) is on target to reach Purfleet in March 2003. Its back up train will then be returned to Swanscombe and attached to a second TBM that will dig the upline tunnel. As the TBM travels forward it has been placing concrete ring segments to reinforce the tunnel.