THE VAST AMOUNT of geotechnical work offered by London's long-awaited east-west Crossrail scheme looks closer to realisation.
A review of the business case for the project by former Network Rail deputy chairman Adrian Montague made a clear argument for it, transport secretary Alistair Darling said last month.
But at a cost of £10bn it was a huge challenge to deliver and fund, he said.
An increase in business rates in London is expected to raise £2bn, with the government finding the rest.
Parliament will debate the project this autumn.
Darling said the price was too high and he has told project promoter Cross London Rail Links (CLRL) to find ways to make the scheme cheaper.
The core of the line will run in 30m deep tunnels between Paddington and Liverpool Street stations, with extensions to the east and west of the city, offering a wealth of opportunities for geotechnical firms.
Montague's report said axing a proposed branch to Richmond and Kingston and replacing it with one to Maidenhead via Heathrow Airport would bring capital costs down from £8.9bn to £8.6bn. Whole life costs would fall from £13.5bn to £11.9bn.
The Richmond/Kingston branch was strongly backed by the Strategic Rail Authority (SRA) because it would relieve congestion at Heathrow.
But in July the government rail review wound up the SRA and made the project a joint venture between the Department for Transport and London mayor Ken Livingstone's Transport for London.
Darling said the case for a limb to Richmond was relatively weakly developed and an extension on the western side to Maidenhead might be a better solution.
'This would be a key change, and would align directly with key review concerns about the scale and deliverability of the project and the number of interfaces it has with the national railway, ' he said.
The Montague review also raised concerns that CLRL's proposed peak service level of 24 trains per hour in the central section might not be achievable because of crossovers with main line trains.
It also questioned whether there will be sufficient capacity in the construction industry for the scheme to be delivered on time and without soaring labour costs.
It added that other potential projects tied to London's Olympic bid and the regeneration of the Thames Gateway would increase the pressure on market capacity. As a result, staged construction would require careful consideration.
Promoters of the rival London Regional Metro (LRM) bid, drawn up by Arup/AECOM, seized on the findings as vindication for their scheme, despite Montague's report dismissing the LRM plan as not offering substantially new thinking.
If Crossrail gets the go-ahead, tunnelling could take place between October 2008 and August 2010.
Spoil from tunnels on the Crossrail project could be used to build up the River Thames floodplain ahead of future development, project promoters say.
The suggestion comes as engineers try to find cheaper options than landfilling construction waste, following the introduction of the EU Landfill Directive last month (GE July 04).
'We'd like to avoid paying landfill tax so we're looking at using excavated material to raise flood plains on development sites, ' said Crossrail head of operations and development Keith Berryman.
He added that most of the spoil would be uncontaminated so could be also used as capping material for landfills. Most of the 8Mm3 of tunnel spoil between Paddington and Stratford stations would be 'good, clean clay', he said.
A Crossrail spokesman confirmed a landfill site in Pitsea, east London, had been identified for this use.