Channel Tunnel Rail Link – St Pancras

Project Details

Client Costain as part of the CORBER JV for Union Railways (North) Ltd, a subsidiary of London and Continental Railways (LCR) , project managed by Rail Link Engineering (RLE)
Date 2003-2007
Skills Planning & Programming, Construction Management
Value Est. £670m

Project Description

Costain as a part of the CORBER JV with O’Rourke, Bachy Soletanche and Emcor Rail delivered the outstanding new Channel Tunnel Rail Link Eurostar international terminal at St Pancras.

The original station building, the historic Barlow train shed, was fully restored and, newly constructed train decks on the east and west side of the station, increased the number of rail platforms from nine to thirteen. In addition, the ‘Thameslink Box’ subsurface station was built, effectively replacing the existing King’s Cross Thameslink Station. Originally built in 1868 by the eminent railway engineer Sir William Barlow, St Pancras International has been painstakingly refurbished and developed to become the finest rail station in Europe.

Works undertaken during the redevelopment included the construction of a 500m long subsurface secant pile box, additional extensive piling, demolition of existing brickwork approach viaducts, service diversions and highways work on some of the busiest roads in North London, the construction of a reinforced concrete frame and elevated train deck, and significant elements of the mechanical and electrical fit out. The station extension also included an aluminium-clad louvre blade and glass roof, a glass atrium entrance and glass screen façades.

LBA Role

LBA provided construction planning and technical support during the tender period and, following award of the contract, provided interim planning and programme support and construction management to the CORBER JV during the construction phase, as an integral part of the project management team.


Project Highlights

  • Following demolition of brick rail arches and preparation for piling of the East Deck Extension, work was brought to a halt by the discovery of a mass grave dating back to the Great Plague. Over 7000 bodies were exhumed and removed off site. The resultant 3 month delay required the whole job to be re-sequenced within the original programmed timeframe;
  • Construction of the Thameslink Box. Approximately 12,000 cubic metres of concrete was placed to form the box base slab, with steel reinforcement cages pre-fabricated off-site and delivered on a ‘just-in-time’ basis to ease congestion both at the base of the box, and at surface. Despite the need to completely re-plan the works, the Thameslink Box was built in just 35 weeks of dayshift only work using ‘top down construction, against the initial proposal of 27 weeks of 24 hour working, following lobbying by residents and local authority refusal to approve 24 hour working;
  • Construction of the Deck Extension. Due to its huge area and expected differential settlement, the deck was articulated by a complicated arrangement of movement joints. Construction of the deck extension was also complicated by the need to keep Midlands Mainline services running throughout the works. This was achieved by building the Eastern half of the extension first, to become a temporary home for Midland Mainline trains during the subsequent construction of the West Deck
  • Restoration of the Barlow Shed. The refurbishment of this grade I listed structure required a number of different approaches both modern and old, with many difficult technical challenges.