Railways radiated from Ashford in four directions before the arrival of CTRL but despite the large marshalling yards and railway workshops the tracks there were never configured to receive a major junction with CTRL.
Much of that is being put right with Mowlem's £60M Contract 434, which has to integrate the junctions to and from CTRL both at Ashford and the Dollands Moor international freight yard near Folkestone.
But getting from no CTRL to a fully meshed-in high speed rail link is proving to be a long and very bitty process.
There are 21 different principal stages in the trackwork layout from the start in August 1999 to the finish in November 2003. Each stage involves some sort of railway possession work of between 28 hours and 52 hours and every possession must be booked and planned for in detail 18 months ahead.
Typical of these was moving the Maidstone lines out of the way of Skanska's piling and heavy civils work for the cut and cover tunnel to carry CTRL under the west end of Ashford.
First the tracks had to be swung out of the way then they had to be swung back in again over the top of the completed tunnel.
Everything had to be coordinated in the finest detail with the many other designers and contractors involved, and with Railtrack.
A similar procedure was needed at the other end of the town where the Canterbury tracks curve away through the line of the now two thirds complete viaduct that will carry the CTRL over the top.
Safety is paramount on all of this work because much of the preparation has to be done adjacent to live railway tracks.
Third rail DC is the standard system on the existing lines at Ashford. CTRL and its stopping tracks switched through Ashford International will all have high voltage AC catenaries. Mowlem is responsible for putting in 300 stanchions and erecting 7km of these.
Extensive adjustments have also to be made to the signalling system which is the most safety critical work of all.
Many signals at Ashford have to be upgraded to the latest Train Protection & Warning System standards. One of many issues that had to be resolved at Ashford was the compatibility between the different power systems and the signalling set up.
Unlike CTRL - which is essentially a French design of permanent way, signalling and power systems - almost everything in Contract 434 relates to Railtrack infrastructure and is designed to UK standards and approved by the Compliance Review Group .
Mowlem is now 40% through the contract by value following completion of the link from the Maidstone line at Beechbrook Farm to the first reception siding of the depot for CTRL's, separate, main tracklaying contract.