Surrounded by historic listed buildings, the huge overhaul of King's Cross station in London - including main line and Tube networks linking the Channel Tunnel high-speed link - requires the highest standards of construction management.
Adrian Greeman finds out how everything is fitting together
KING'S CROSS and St Pancras stations now form London's busiest construction site. The new Channel Tunnel high-speed rail link surfaces just north of the adjacent stations and construction of the huge international St Pancras terminal is under way. At the same time, London Underground is restructuring and expanding Tube stations and underground passenger links to cope with the inevitable increase in traffic.
At a mere £300 million, the Underground scheme is the smaller of the two projects.
'But it is at least as complex, if not more so, than the CTRL job, ' says David Hills, partner at Hornagold & Hills, which is providing project management support to project manager Infraco Sub Service Lines. 'To begin with, the site lies between three major historic buildings: St Pancras Chambers, one of the best loved buildings in the UK; the slightly earlier King's Cross railway station, also Grade I listed, and the Great Northern Hotel.'
The latter has mere Grade II listing but still has to be carefully protected during a 70,000 cu m excavation taking place just metres away.
Both stations always require plenty of access room for passengers and the trains must keep running, too. They must also continue to connect not only to three different Tube lines, the deep Northern and Piccadilly and the sub-surface Metropolitan, but also to the Thameslink line passing underground through central London.
'If all these lines and tunnels were not enough, there are also several old disused tunnels, pipes and large sewers to contend with, ' adds Mr Hills.
Problems of access, logistics and co-ordination are further compounded because St Pancras Chambers is also, finally, under renovation, while the once grand Victorian hotel is set to become a modern establishment with super luxury apartments at its top level.
Then there is Euston Road, one of London's busiest through routes and the northern boundary for Ken Livingstone's traffic congestion scheme. It is lined with shops and commercial properties, including retail outlets in the listed forecourt wall space of St Pancras.
All this throws up a multitude of issues for the 100strong project management team. Not only are the design and the control of the physical work exceptionally complex - just for building and ground movement monitoring there is a £2.6 million specialist contract with Sol Data - but dozens of third parties, statutory bodies and agencies have to be dealt with.
And there are public relations to think about, not simply for a high-profile project, but locally, with Camden Council and community representatives.
'Soft management', as Mr Hill's deputy, Martin Gosling, calls it, has taken up more than 50 per cent of the senior team's time at this stage of the project.
These are elements outside construction, design and cost management - co-ordinating and interfacing, keeping up with necessary lead times on permissions and legislation, cajoling and persuading and convincing various managers to take up proposals and changes.
'It is about building up trust and working relationships, ' says Mr Gosling. 'Particularly, showing people that you know what you are doing and are professionally-minded, having their interests in mind as well as your own.'
Those interests are significant, he says. For the railways alone there is Network Rail and its different divisions and the railway operating companies, all with their own concerns to keep trains running, as well as for the condition of the infrastructure itself.
Transport for London and the Highways Agency have other needs for Euston Road than as a place holder for buried services as two lanes need to be kept open each way at all times.
English Heritage is also not about to allow one of its most famous possessions, St Pancras Chambers, to move around and crack up.
'Design sequences for the forecourt excavation had to be thoroughly worked through with them, ' adds Mr Gosling. 'And where parts of the forecourt have had to be removed it has insisted that every original 1860s kerbstone and cobble is tagged, indexed and stored for replacement.'
At King's Cross, deemed equally important, a special glazed weather canopy to protect arriving coaches has been dismantled, but will later be reinstated.
'We have had to interface every step of the way, ' says Mr Hills. That means crucial communication with London Underground itself via the SSL Infraco and, most importantly, SSL must satisfy Her Majesty's Railway Inspectorate. So too, in other areas of the project, must Network Rail. Ongoing corporate changes at all of these have only served to complicate matters.
And then there are risk issues. The team makes sure to work through design and construction issues with a series of brainstorming sessions to try and identify and quantify all the risks in each operation beforehand.
This has worked well during both tunnel slicing operations and the shorter Thameslink tunnel section was completed this Christmas in just four days of the planned five-day possession.
'Harder' construction management is coming to the fore now as the work accelerates. The team uses Primavera software for construction programming and control, tendering, resource use and similar issues. It has 'developed the organisational structure to an unprecedented degree' says Mr Gosling.
According to planner Gerry Lambert, most projects use parts of the system but do not take full advantage.
'We are close to the 'Holy Grail' of full procedure, ' he says. The software provides immediate time, supply and cost information across the whole project and takes into account changes made to any part of it. 'You know where you are all the time and therefore where you are going, ' he adds. And that, also, should be the result of this mammoth project.
Victorian gas pipes head west
AFTER a full exploration of services on Euston Road, numerous utilities had to be moved to make way for the western ticket hall - but as could be expected in an area which includes the world's first major gas network, mapped positions did not reflect the spaghetti in the ground.
Ancient pipes were sometimes degraded and splicing for parallel diversions would prove difficult. It was proposed to revitalise a disused Victorian connection tunnel which curved under St Pancras to re-route lines.
'It would save time, take out risk and cut back excavation on Euston Road, ' says Mr Hills. But discussions were still needed with each utility - particularly Transco which had 915 mm and 305 mm cast iron gas mains to move and Thames Water which also had a 915 mm pipe.
Their requirements had to be worked back and forth through Network Rail and Her Majesty's Railway Inspectorate among others.
'A protective substructure had to be built in the tunnel, ' says Mr Hills, 'which meant ensuring the brick arch structure's stability, and a short cut and cover section was needed too.'
Just the ticket
LONDON Underground has been concerned about its cramped King's Cross ticket hall since the tragic fire at the station in 1991. Alongside safety is demand: passenger numbers will grow when the terminal is completed for high speed trains to Paris and Brussels via the Channel Tunnel Rail Link.
The Government-funded London Underground scheme will expand the circular sub-surface hall back under the station forecourt, creating 'back-ofhouse' space and retail areas, thereby expanding the main concourse.
Meanwhile a new ticket hall will go in the cramped space between the untouchable St Pancras building and the busy Euston Road, sitting just above the platforms of the live subsurface Metropolitan line which run underneath.
'All that was to be done as phase one, ' says David Hills of Hornagold & Hills, 'because a second stage expansion would be required only if the high-speed link went ahead.' It has, so phase two is also under way and is due for completion in 2006.
A new cathedral-style northern ticket hall will be created underground between the two main line stations, serving as the main concourse for international passengers connecting to deep Tube lines. New escalator tunnels and a footway underneath King's Cross station's platforms and lines are also needed.
Hornagold & Hills organised several brainstorming meetings before slicing up of the Metropolitan line tunnel. The new western ticket hall must sit partly over this Victorian brick arch tunnel but there was not enough space below ground so a 60 m length had to be flattened.
The work raised numerous issues not least in obtaining night and weekend possessions on a busy tube line, but on traffic diversions on Euston Road and exceptionally careful sequencing of excavations just in front of St Pancras Chambers to avoid settlement.
Risk assessments led to a switch from shorter night possessions to weekends and to full rehearsals with scaffolding and sequences. Even so, a cautious start was made with the earliest slices removed from the tunnel being just 1 m long and a new flat roof was concreted in. Later, the lengths were expanded to 3 m on each of the possessions.
Project sponsor and provider of funds: Department for Transport
Project manager: Infraco SSL
Project management support: Hornagold & Hills
Lead designer: Arup
Phase Two principal contractor: Costain Taylor Woodrow jv
Subcontractor Phase One Western Ticket Hall: Scanmoor
Subcontractor Phase One Tube Ticket Hall Thameslink Quickbridge: Gleeson MCL
Phase Two piling: Stent Foundations
Phase Two tunnels: Morgan Beton Monierbau jv
Architect: Allies and Morrison