In order for this to happen, the existing Thameslink tunnels between Kentish Town and King's Cross Thameslink were closed between 11 September 2004 and 15 May 2005 while the works were carried out.
För att bygga spåren var tunneln mellan King's Cross Thameslink och Kentish Town stängd mellan 11 september 2004 och 15 maj 2005.