King’s Cross is one of the UK’s busiest interchanges, which often equates to a miserable experience for passengers. However, Network Rail is about to change all that. Ed Owen reports.
When built, the twin London terminus stations of King’s Cross and St Pancras were mired by rivalry.
Constructed by competing companies, King’s Cross opened in 1852 as the London terminus for the Great Northern Railway.
St Pancras was built in 1868 by Midland Railway, designed to outshine its rival with the now famous train shed designed by William Henry Barlow.
When the companies were nationalised, St Pancras eventually fell into disrepair, and was close to being demolished. In the meantime King’s Cross prospered as one of the busiest terminals in London.
Victorian grandeur brought up to date
But King’s Cross is well overdue for a refurbishment − as it is fast approaching capacity.
Over £400M is being invested in the station, funded by the Department for Transport and Network Rail, to give it the capacity it needs for the future while also exposing its Victorian grandeur and bringing it right up to date for the 21st century.
Although Network Rail’s project director for the new scheme to update King’s Cross Ian Fry is unwilling to admit it, the rivalry between King’s Cross and St Pancras persists. St Pancras is now the toast of the railway world following its spectacular refurbishment and rebirth as terminus to High Speed 1.
“We are adding an iconic piece of 21st century structure, something not done at St Pancras.”
Ian Fry, Network Rail
“At King’s Cross, we are going to restore the Victorian architecture, designed by Lewis Cubitt. Then we are going to be adding an iconic piece of 21st century structure, something not done at St Pancras,” says Fry.
The work at King’s Cross will strip the building back to its original brickwork on three sides, install a new platform and erect a huge diagrid half-dome roof.
Around 47M people use the Network Rail station every year and the work will boost the capacity by another 10M − but it also aims to give passengers a better experience. Transport for London is also enlarging the Underground portion of the station, with work there due to finish next year.
Because of the station’s poor reputation, Fry says: “Most passengers arrive just in time to catch their train, and find the quickest routes in and out.”
King’s Cross: development plans
- Cubitt wrought iron roof refurbished above the heads of passengers, 2,200m2 of photovoltaic panels will be installed providing 10% of the station’s power
- New platform created to take trains on the East Coast Main Line, increasing capacity
- Eastern range buildings have already been refurbished with brickwork stripped back
- Western Range buildings will house operational staff who currently occupy the Eastern range buildings
- Arup designed diagrid canopy will create four times the space of the existing station
- Grade I listed Great North Hotel’s ground floor will be knocked through to make a continuous space
- Old canopy demolished to create a new civic space for passengers
- St Pancras: the rivalry between the two stations looks set to be reignited
The new station will force these passengers to find new ways to navigate their way around, but the pay-off promises to be something enjoyable that will give them a reason to stay longer.
Which leads nicely to the one thing that is striking about King’s Cross today − its sheer ugliness. The first piece of good news is that the hideous green canopy that bears the “King’s Cross” sign will finally go as it almost completely obscures the handsome Grade I listed brick structure that forms the main station building behind.
According to Fry: “The existing canopy was installed with temporary planning permission in 1972. We will finally get rid of it, which will expose the original brickwork and structure.”
“We will finally get rid of the existing canopy from 1972, which will expose the original brickwork and structure.”
Ian Fry, Network Rail
Like St Pancras, the Victorian structure at King’s Cross will be renovated and improved. A Kier/Corus team will carry out the work in a restricted space right above the heads of passengers, replacing worn parts of the wrought iron Cubitt roof of the train sheds with original materials.
According to Corus Rail Infrastructure Services principal engineer Lee Owen the main concern on the job is to keep the roof barrels stable while renovations are carried out on support columns 12m apart along the 233m roof length.
Barrel supports will be grit blasted back to the wrought iron underneath, dismantled, repaired and replaced. To keep the roofs stable the contractor will be installing temporary transverse ties across the barrels “to counteract the out of balance forces that come into play in the staged removal”, says Owen.
New energy and capacity
When the roof is finally reglazed, 12,000m² of laminated glass and a further 2,200m² of photovoltaic (PV) panels will have been installed, which should provide 10% of the station’s energy requirements.
“The PV panels will take-out some of the light, but once the new glazing is in, it will be a much lighter structure,” says Fry.
Owen’s team will also work on the new platform to take trains on the East Coast Main Line, increasing capacity on the line. The platform will be located under the Eastern Range − the renovated buildings that are the first milestone to be completed at King’s Cross.
Owen says the station has very shallow foundations and a significant amount of testing has taken place to make sure installing the new platform and new foundations will not damage the buildings. “We will not be installing extra piles, but putting in an extra 300m long track slab,” he says. “Which will be much easier to install.”
The Eastern Range is now housing operational and non-operational staff until the Western Range of buildings is repaired, when operational staff will move there.
A landmark canopy
The most striking change to the station will be the new concourse canopy. The existing canopy will eventually be removed and the area bordering Euston Road will be left as a civic space and the entrance moved to the western side bordering Pancras Road, which was the location of the original entrance way, and a new concourse built.
Bordering the western wall of King’s Cross, and the very close by Great Northern Hotel will be a huge Arup-designed canopy.
Fry describes it as: “Something like the dome at the British Museum − but much larger.”
- 2008 Main tran shed roof renewal starts
- 2009 Work on western concourse begin
- 2010 New platform complete
- 2011 Restoration and reglazing of roof complete
- 2012 Western concourse opens for the Olympics
- 2013 Demolition of existing concourse and new public square built in front of station
This 1,200t aluminium and glass half-dome will cover an area of around 8,000m² when complete. But with an added mezzanine area, passengers will have more than four times the space than the station currently provides. The dome looks set to become a London landmark.
The dome will be 30% glazed − at its base and at its top. Arup structural engineer Ed Newman-Sanders explains the basic design: “The structure of the roof comprises a diagrid, similar to the roof of the [Reading Room at the] British Museum,” he says.
“The structure of the roof comprises a diagrid, similar to the roof of the [Reading Room at the] British Museum.”
Ed Newman-Sanders , Arup
“The difference being that ours is not a pure diagrid. We have a structural hierarchy in which the radial members are rectangular and the diagrid members are circular. The roof comprises a doubly curved diagrid shell structure which is set-out on a radial geometry.”
Where the semi-circular roof meets the Western Range, the diagrid falls to the floor in a cascade the designers refer to as “the funnel”. In addition to the funnel support the roof will be cradled on 16 points they call “trees”.
Each tree carries four branches − three facing towards the middle and one towards the rear. Two trees adjacent to the Western Range have been labelled as super-trees as they are required to carry a significant 600t horizontal load 4.5m off the ground.
“The roof is not a perfect semicircle, as the boundary interface with the Great Northern Hotel is not perfect,” says Newman-Sanders. “And there are outcrops protruding from the Western Range which complicated the geometry.”
Coherent and useful spaces
Cubitt also designed the Great Northern Hotel beyond the south west corner of the station. This is another Grade I listed building and will also receive a complete refurbishment.
To make the new space under the canopy coherent, the ground floor of the hotel will be knocked through to make a continuous space through from the hotel arcades to the station.
One final piece of civils will never be seen by the public. The team has installed hundreds of concrete piles to create an access ramp and delivery point for lorries in the area just to the north of the concourse.
This meant installing 900mm diameter piles to form contiguous pile walls bored an average of 32m deep, although some are driven as deep as 55m.
- The Eastern Range Laing O’Rourke, Costain, Arup and John McAslan & Partners
- Train shed roof Kier, Corus, RDG Associates
- Train shed roof enabling works Morgan Est and Mott MacDonald
- New concourse and dome Arup, Taylor Woodrow, MACE and Balfour Beatty Management
The piles have created a huge room, 12m deep, 30m across and 50m long, which leads to an access ramp exiting onto the Goods Way at the northern end of the site.
Creating the service yard also meant protecting the original station building during piling, and sheet piles were installed between the bored piles and the station to ensure there was as little movement as possible. “So far we have had not problems,” says Fry.
“What we are doing here will exceed St Pancras. It’s my view anyway.”
Ian Fry, Network Rail project director
This service yard will also act as the support for new structures to be built above. “We have used 3m and 4m beams to transfer loads, to give the developer the chance to vary plans in say 50 years,” says Taylor Woodrow project manager Peter Walsh.
Juggling four main sites and a number of smaller jobs running alongside would be a difficult enough job, but this will all be done on a live site. Fry again touches again on a possible rivalry with St Pancras, which was closed to the public during its refurbishment. “What we are doing here will exceed St Pancras. It’s my view anyway,” he says.