King's Cross station's £500m redevelopment: King of King's

When the Midland Railway built St Pancras station in 1868 the plan was to trounce the Great Northern Railway’s King’s Cross terminus over the road. When it opened, St Pancras featured the largest single-span roof train shed in the world, fronted by an extravagant Gothic hotel. King’s Cross station was elegantly simple, and modest by comparison with just two platforms fronted by a yellow brick facade.

Today, with St Pancras reinvented as an international station with a beautifully refurbished hotel, the contrast between the two stations is even more marked.

King’s Cross station struggled to cope with passenger volumes from the beginning. A ramshackle collection of sheds grew in front of the station soon after it was completed
and was replaced in 1972 by a large canopy housing the ticket office, shops and waiting space. Known as the southern concourse, this is still there today.

“King’s Cross has an awful lot of shortcomings and doesn’t represent UK rail very well in what should be a flagship station,” says Ian Fry, Network Rail’s programme director for King’s Cross station. “The southern concourse was built with temporary planning permission and has insufficient capacity now and for the future; retail areas are cramped and disjointed and the building needs a lot of structural repair.”

But Network Rail is addressing the issues. Fry is overseeing a £500m refurbishment of King’s Cross which, when complete, will mean it will once again rival St Pancras as a landmark station and a key London terminus.

The ugly southern concourse will be swept away and replaced by a public square so that passengers can fully appreciate the station’s original facade. The station will include a new concourse on the west side, shops and restaurants.

Old railway company rivalries are feeding through into this project. “St Pancras is a source of national pride and is a hard act to follow,” says Fry. “It was designed to be better than King’s Cross and I can’t change history as St Pancras is a fantastic piece of architecture.” The refurbishment of St Pancras was always going to look good,
he says, but adds that the new additions, including the extension needed to house long Eurostar trains, are less successful.

“We are going to do better,” he says. “The new interventions here will be the best in 20th-century architecture.”

The problems with King’s Cross

The team has faced significant challenges realising this ambition. Creating sufficient space for waiting passengers took years of planning and negotiations with English Heritage and Camden council as King’s Cross is grade I-listed. The original station is smaller than its much grander neighbour so ways had to be found to manage passenger flows through what is the UK’s busiest transport interchange.

In addition to the planning challenges, parts of the building were in very poor condition. Leaking roofs on the eastern side of the station had been fixed crudely by securing three sheets of polythene to the roof with six-inch nails driven through the slates to the rafters below. Finally, all the work has had to be carried out with the station remaining

The southern concourse was needed because the trains stop only a few metres from the main facade, leaving no room for passenger facilities. Architect John McAslan says a range of options for new facilities were explored. The most obvious, extending the platforms north of the main building to create more space at the southern end, was out of the question because the lines converge into tunnels as they leave the station leaving no space between the tracks.

The solution

Eventually, the team settled on the construction of a new concourse on the western side of the station. There was plenty of space, plus it linked the suburban train platforms on the western side of the main station with the rest of the building and the new underground northern ticket hall. “What everyone really liked was that it connected really well with the underground, the suburban train platforms and it was in a direct relationship with St Pancras,” explains McAslan. “It allows the southern concourse to be demolished and the station to return to its original character.”

McAslan has designed a striking semi- circular concourse. Its shape echoes the curved form of the Great Northern Hotel that sits on the southern side of the new concourse. The concourse is 5.5m high at the entrance and rises to 19m, the full height of the station, where it abuts the western side. The roof is made up of a combination of aluminium and glass triangular panels supported by 16 tree-type columns. Inside, a mezzanine will have food and drink outlets for passengers and at ground level there will be shops and three times as much space for waiting passengers.

Passengers will enter the station at ground level and pass in front of the end of the platforms to catch trains. The platforms nearest the entrance have been slightly shortened to give more room. The station can also be accessed directly from the mezzanine via a new footbridge that links the west side of the building to the east. Escalators and lifts will take passengers from the footbridge down onto the platforms. All passengers will exit the station via the south facade onto the new square.

“The key driver was how to keep King’s Cross running without cancelling any train services or taking away any facilities,” explains Fry. “This was a major challenge.”

The solution was to divide the project into seven phases, which have been tackled by several different contractors.

The eastern range

The first package was the refurbishment of the eastern range, a terrace of two-storey buildings. “This was critical to the overall project as the station was run from offices
on the western side, which is the nerve centre of the station,” says Fry. Once the eastern range was refurbished, the office workers could move over from the west range, freeing it up for refurbishment.

The eastern range was tackled by a Laing O’Rourke/Costain joint venture and completed in mid-2009. The job was more involved than Fry envisaged because it was in very bad condition and English Heritage was very particular about the conservation work.

Refurbishing the platforms

Refurbishing the existing platforms meant taking them out of service. Extra capacity has been created by building a new platform under the eastern range in a space once used as a cab rank. Called platform 0, the job was carried out by Carillion and involved extensive track configuration to keep the same amount of space in the sidings. The work was finished in May 2010, allowing work on the platform refurbishment to start.

The central platforms have been refurbished in pairs by contractor Vinci.

The work involved new drainage under the platforms, the addition of tactile strips on the platform edges, and resurfacing. The lift and escalator links for the new footbridge have been put in at the same time. Three sections joining these together were installed over Easter when the station was closed. The last section will go in over the August bank holiday. The bridge elements are very slender to minimise the visual impact on the station with glass balustrading that is being installed at night.

An integrated approach to CCTV, fire extinguishers and signage means these elements feature a common design by John McAslan and are attached to poles on the platforms. “It means a massive reduction in clutter around the station,” says Simon Goode, John McAslan + Partners’ project director. Platforms two to seven are finished and work is just starting on platform eight.

The most invisible part of the project is the creation of an underground service yard to the north of the station on land owned by Argent. A tunnel links this to the station and will be used for deliveries to retail outlets and food and drink for on-board train services. It will eliminate the need for trolleys trundling along the platforms, leaving more space for passengers.

Roof refurbishment

Back in the main station work is progressing on the refurbishment of two barrel-shaped roofs over the tracks. “Everything has to be stripped off the roof, the structure stripped back to bare metal and rebuilt without cancelling a single train,” says Fry.

On the platforms the only evidence of roofing work visible to passengers is a scaffolding rig that fits neatly under part of each roof of the main station. This provides a safe working platform for workers on the roof and protects passengers from weather and any falling objects.

On the roof 32 layers of paint are sand-blasted off the wrought iron roof structure once the old translucent corrugated plastic sheets and roofing felt has been stripped
off. The structure is painted a blue-grey colour and the purlins and glazing bars reinstated. New Welsh slates are being used for the lower roof sections and five overlapping layers of glass clad the upper side of each roof and are topped by a lantern with integrated PV cells that add up to half a football pitch in area. New leadwork links the roof to the south facade and keeps the joint watertight.

Everything has to be taken on and off the roof via a deck at the northern end of the station, but Fry has an appropriate solution: “I’ve got my own railway down each side of the roof and in the middle,” he beams. Workers can roll skips with materials and waste along tracks mounted between the two roof barrels and at the sides.

The western concourse

Vinci’s biggest package at King’s Cross is the £180m western concourse and western range refurbishment works. “The biggest challenge is logistics and managing the work with limited access,” says Fred Garner, contracts director of Vinci’s civil engineering division. “We’ve got the entrance to London Underground’s northern ticket hall and the route through to platform eight. We’ve had to work around that and maintain the taxi pick up and drop off outside the station, plus maintain deliveries to the station.”

The western concourse is being built above the new London Underground northern ticket hall. Arup was the engineer for this as well as the concourse so the piles for the roof were put in when the ticket hall was built. Vinci has had to create the pile caps supporting the 16 tree columns needed to keep the roof up.

The western concourse roof structure is formed from radial beams linked by diagonal members running from the edge of the concourse back to the west side of the station. The beams were supplied in sections as “ladders” built offsite. These were delivered at night and welded together during the day. “As there is no storage here it’s been done on a just-in-time basis,” says Garner. Crash decks protect the pedestrian routes threading through the site, but all heavy lifting has to be done at night as the crash decks only provide limited protection.

The whole roof has been supported by an incredibly dense forest of scaffolding as it is not self-supporting until finished. Tunnels provide access to the western range through the scaffolding. The cladding consists of glass at the perimeter of the concourse and at the roof apex, and aluminium was used elsewhere to stop the concourse turning into a giant greenhouse. Now the structure is up and the cladding finished the roof is being gradually de-propped ready for fitout.

The western range

Vinci is also refurbishing the western range. Part of this work including reinstating buildings in the so-called “bomb gap”, which were destroyed by bombing in the Second World War. “When I first joined the project I thought it was an anti-terrorism measure,” laughs Fry.

A concrete frame has been built around an underground vent shaft and new brick facades to the front and rear. The old parcels office is being converted to a pub with an attractive wooden panelled atrium at its heart. In a nice historical touch, the original ticket hall is being reinstated. This will be a lofty space extending almost to the full height of the building. The entrance to the station from the concourse has been inserted at the southern end of the western range. This has four columns supporting the portal frames needed to support the building above.

The southern concourse

The western concourse will open in March 2012 and will transform the passenger experience (not before time). But the station facade won’t be fully revealed until after the Olympics because the southern concourse is being retained due to increased passenger numbers. According to Fry, getting rid of the southern concourse is more involved than meets the eye because of the underground below. “Taking it out is a substantial piece of work,” he says. “The slab needs repairing and strengthening and waterproofing and we have to maintain passenger flows out of the station.” Because of this the work will be done in sections.

Once complete the space will be landscaped to a design by architect Stanton Williams and by the end of 2013 this massive, complex project will finally be at an end. King’s Cross station is unlikely to ever trounce the architectural glory of St Pancras, but this work means it will become a very civilised neighbour and a worthy equal.