CONSTRUCTION OF the Channel Tunnel Rail Link (CTRL) hits a milestone later this summer, as engineers start tunnelling the high speed route under London's streets.
Tunnelling work will form the meat of the project's £3.3bn Section Two which runs 34km from Ebbsfleet in Kent to St Pancras Station.
Engineers are not sitting around waiting for tunnel boring machines (TBMs) to arrive, however. They have been preparing for this new phase since last July, and 16% of this section is already complete.
In central London, preparation work for a refurbished and extended St Pancras Station and approaching new Eurostar lines is ongoing.
Around the site, utility and road diversions are continuing, together with railway diversions, earthworks, creation of retaining walls, piling and construction of a temporary railhead on the adjacent King's Cross lands for bringing in materials.
To the east, excavation of three deep tunnel vent shafts at Corsica Street, Barrington Road and Woodgrange Road is pushing ahead, plus assembly and testing of TBMs.
At Stratford, diaphragm walling and excavation for the 1km long box that will eventually house a new station also continues. A tunnel segment production factory has been built on the site.
East of Dagenham, pile load testing is complete for the planned viaduct to carry trains across the marshland north of the Thames.
South of the river diaphragm walling for the tunnel approaches pushes on at Swanscombe, along with box construction for the second new station at Ebbsfleet.
As the focus of construction moves to London, it is easy to forget progress on Section One of the works running 74km from the Channel Tunnel in Folkestone to Fawkham Junction in Kent.
With civils work 83% complete and on track for operation in 2003, activity has turned to tracklaying and lands caping, and a vision of the completed railway becomes clearer.
Most notably, drivers on the M2 can now view the completed 1.3km push-launched Medway bridge and 3.2km North Downs tunnel.
Ashford residents can also see the completed viaduct and cut and cover tunnels that will carry the 300km/h trains to and from the existing Channel Tunnel interchange.
Nina Lovelace INFOPLUS www. ctrl.co.uk