The new teminal at St Pancras encounters the complexities of adding a contemporary extension to a Grade I-listed building
The Channel Tunnel Rail Link (CTRL) is the first major new UK railway for more than a century. The project was authorised by parliament in 1996 when London and Continental Railways (LCR), as the new owner, became responsible for the construction, operation and finance of the project.
Foster and Partners created a masterplan for the 52ha King's Cross site, including a design strategy for the development of St Pancras, in 1997.
This was adopted by Rail Link Engineering, a consortium made up from the engineering shareholders of LCR comprising Ove Arup & Partners (engineering) Bechtel (project management) Sir William Halcrow and Partners (tunnelling) and Systra (French railway network constructors). RLE is responsible for the design and project management of the rail link.
Taking over a project conceived by such a high-profile architect was clearly a sensitive issue. RLE inherited Foster's plans to extend the existing William Barlow-designed building at its northern end by the addition of a contemporary glazed shed. It also maintained Foster's plans for the replanning of Barlow's shed.
The RLE team took responsibility for the detailed design of the main roof and transition roof and the side and entrance screens of the new building, and also for heritage renovation works to the Barlow shed. It was also responsbile for obtaining the relevant approvals from English Heritage and the London Borough of Camden.
Track record Alastair Lansley, lead architect of RLE, is a man with a mission; heading a team of some 900 staff, he is a rail man through and through. 'Liverpool Street took ten years of my life, this will take another ten.' The sheer scale of the operation is impressive even before you add the complexities of a contemporary extension to a Grade I Victorian gothic building, a Eurostar tunnel under half of London, two new Underground stations - and the fact that the Midland trains have to keep running throughout.
In its time, the St Pancras complex was not only opulent but cutting edge, incorporating 300 rooms, hydraulic lifts, revolving doors, fireproof floors and a world-class clear span roof. Originally designed under the guidance of William Barlow, the London terminus for Midland Railway opened in 1868, eight years before the addition of Sir George Gilbert Scott's Midland Grand Hotel.
Lansley describes it as 'incredibly hitech at the time. It had the biggest roof in the world; a gutsy building, bombed in both wars and still the roof held.We have the original drawings from Kew records office and will be interpreting those.' Together with nearby Euston Station, St Pancras predominantly serves the Midlands.
The aptly named Midland Hotel closed in 1935, when it became uneconomical to run. Almost demolished in the '60s, it was reprieved when granted Grade I-listing status.
Under the new banner of St Pancras Chambers, it served a grey period as offices for British Rail, but in the '80s failed to achieve a fire certificate and was closed down. Much of the interior finishes were destroyed during this period. A £10 million refurbishment funded by British Rail and English Heritage was completed in March 1995, restoring the exterior to its original condition. The hotel is being brought back to life by the Chambers Group Consortium, made up of the Whitbread Hotel Company, Manhattan Lofts and RHWL.
Section one of the high-speed Channel rail link from Folkestone to Ebbsfleet opened on 17 September.
Section two, mostly underground, following the route of the North London line, will emerge at the top corner of the St Pancras site.Why St Pancras?
'It is a fantastic place to end up, linking with the Northern network, it takes you across the Thames and brings you out nearer the City and will help rejuvenate an area of London that was in need. On its way we pick up a brand new station at Ebbsfleet and then another at Stratford, ' says Lansley.
Barrel vaults King's Cross was built in 1852 with the Midland Railway paying a tax to use the station. The Regents Canal cuts across the north of the site and when the King's Cross line was built the decision was made to go under the waterway. However, when the Midland Railway decided to build its own terminus at St Pancras, they elected to go over the canal. This resulted in the platforms at St Pancras being about six metres above those of Kings Cross. The extra height provided space underneath for the storage of beer from Bass, the Midland brewer, for distribution around London.
The height difference, described by Lansley as 'the reason St Pancras has always looked much grander', plays a fundamental part in the current redevelopment. The new station will have the main concourse at street level with trains above. 'Like Covent Garden there will be significant cutouts so that you can view down into the undercroft level of the arrivals.
Conversely this provides a visual link to the trains above you from below, ' Lansley says. The under-platform concourse has been designed around the labyrinth of support columns originally spaced - not just for structural reasons - but in multiples of beer barrels.
The Thameslink line currently passes underneath the tower of the hotel, but will be realigned along the western side of the site where a new Underground station will be built at roughly the same level as the Victoria line. A new ticket hall for King's Cross is being built underneath the forecourt of the hotel. 'This is the spaghetti junction of the Underground. We have just about every tube line underneath here bringing in 1,500 people at a time.We need to get those people into the system and taken away, preferably by Underground or train, not taxi, ' adds Lansley.
Straight but not narrow Managing people movement plays a big part in the project, such as making passengers walk the 400 metres along the platform to disperse them and help the customs process. The brief requires passengers to exit the 13 platforms within 17 minutes. Parking for 300 cars is also incorporated. The wedge of land between St Pancras and King's Cross will become a vibrant public square and provide access to both domestic and international entrances. It is clear, too, that RLE is striving to maintain the building's integrity. Where doorways have to be punched through the east wall to form new entrances, arches are of load-bearing brickwork - there is not a lintel in sight. The roof steelwork finish will be matched to the original colour used when the station first opened.
Unlike the sweeping curves of the existing Eurostar terminal at Waterloo, St Pancras will be dead straight.
To accommodate the 400m trains, an extension larger than the existing shed is being built to the north. A transition roof has been created to allow the contemporary extension to sit with the original Barlow shed.
'Unashamedly, old meets new and the scale is enormous, ' says Lansley.
Part of the reason for its size was English Heritage's stipulation that the view through the original end screen be maintained. This has resulted in the new roof being some 20 metres above the ground. Like a giant flat umbrella, the edges are not sealed but calculations predict that most rain will be caught by cunningly positioned side screens. Structurally, seven pairs of columns, 30 metres apart, straddle the tracks creating a colonnade. Lansley points out that 'it's really saying, in architectural terms, 'I'm holding a bit of railway so I look quite heavy here but now I'm just holding an umbrella so I'm relatively light'. English Heritage has been very brave and cooperative with us.'
Air will be drawn from the top of the Barlow roof and ducted through underfloor vents through the new concourse. This gets over the necessity for unsightly hanging ducts that would have impacted on the look of the original roof. Spent air will be extracted from the halls via upsidedown chimneys and, in the case of fire, smoke could be extracted the same way. The eastern elevation is being completely rebuilt in a pastiche of the original, incorporating the Thameslink Station, food hall and Marriott hotel extension above. The original ridge and furrow roof will be recreated with glazing incorporated within the centre section.
Looking forward to handing the keys over in 2006 and the first public service in 2007, Lansley said: 'It was never going to be easy. I think we should let history decide whether we have got it right or not.'
Michael Hammond is a freelance journalist