THE £500 million transformation of St Pancras station into a new terminus for the Eurostar is providing London with a dramatic new landmark.

It comes in the form of a vast “flying carpet” canopy covering new platforms which extend way beyond the mouth of the Victorian station. The new canopy, held aloft on steel columns that look as slender as cocktail sticks, is an engineering marvel in the spirit of the original train shed which had a span of 75m (246ft), the largest in the world when it was completed in 1868.

Usually platform canopies are little higher than the trains. Here they soar 11m above the platforms, thanks to a requirement from English Heritage that there should continue to be a clear view out of the mouth of the building. Just 28 tubular steel columns support a vast roof which will measure 215m-by-130m.

In contrast, to the graceful curves and massive construction of the original, the new canopy is a minimalist structure of straight lines and right angles stiffened by invisible cross-bracing between the waveform roof lights. It is all the more impressive a landmark as the tracks coming in to St Pancras are 6m above street level, raised on a viaduct carrying them over the Regent’s Canal.

By contrast the lines into the neighbouring King’s Cross station go under the canal in a tunnel with the result that the new canopy at St Pancras hovers above its neighbour.

When it opens in 2007, the six Eurostar platforms will have pride of place with the Channel Tunnel trains reaching from the buffers beneath the restored Midland Grand Hotel to the very end of the new platforms — a distance of 400m. Under the new canopy will be seven further platforms, four serving the Midland Mainline and continuing to bring trains from Bedford, Nottingham, Sheffield and other Midland towns.

The three additional platforms to the east are reserved for new fast trains from east Kent which will use the new Channel Tunnel Rail Link line and cut commuter train times by up to two thirds. The new terminus is a triumph for Arup, the engineers who devised the new fast line from Folkestone which will reduce travelling times to Paris to 2 hours 15 minutes. Several miles of newly completed tunnels will whisk passengers from Stratford in East London to St Pancras in seven minutes.

The architect for the station’s remodelling is Alastair Lansley, the sole remaining member of the British Rail architects’ department who was involved in the £110 million reshaping of Liverpool Street station in the 1980s and now works for London and Continental Railways on St Pancras. He said: “Nearly half the train shed roof will be put back to glass which was lost during wartime bombing. We were worried that this might result in overheating but tests have shown that by returning to the ridge and furrow design of the Victorian engineer, W.H. Barlow, the temperature on the platforms will rise by no more than 5F.”

The second great feature of the new terminal is the cavernous vault beneath the original train shed which will serve as a passenger concourse under the tracks. The vault is supported by a forest of 720 cast-iron columns. This was originally designed to serve as a bonded warehouse for Burton ale and the distance between the columns was precisely tailored to the dimensions of Burton beer barrels brought by rail from Staffordshire. Now it will be filled with shops, cafés and lounges for CIPs (commercially important passengers, in Eurostar argot).

Along the west side English Heritage has sanctioned four cuts in the platforms giving waiting passengers a view from the vaults to the soaring roof of the train shed 37m above.

The terminus may look even better by night. Claude R. Engle, who designed the lighting of the Louvre pyramid in Paris and the new Great Court of the British Museum, said: “At night the Victorian train shed will glow. Instead of the horrible glare you get in some stations from 1,000W overhanging lights, here the light will bounce off the floor so the great train shed above will not be a dark cavern but visible to its full height. We’re using a white light, slightly warmer than incandescent light, which is economic and also very flattering to people.”

Lighting along the platform edges will give the Eurostar trains a glow of their own, he added. The height of the new canopy is also designed to cope with diesel trains which will continue to run on the Midland mainline. “Open sides provide the maximum flow of air across the station carrying the fumes away,” Mr Lansley said.

Mike Glover, the engineer in charge at Arup, said: “The new St Pancras will be different from any other London station. As you wait on platform 13 for the train which will take you in 30 minutes to Ashford, you will look out across London through clear glass screens seeing the trees which rise above the rooftops.”

THE WORKS

• The building of the Victorian train shed involved 100 steam lifts, 1,000 horses and 6,000 men
  
  
• The current extension of the station involved a workforce of 1,000 men aided by 7 tower cranes and a dozen track-mounted cranes
  
  
• While the work was on, all the spoil was taken off the site by train, not by lorry

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