Choosing an upgrade of existing rail lines over the construction of the entirely new HS2 high-speed rail would bring about 14 years of regular weekend closures, according to a Government-backed study.
The report prepared by Network Rail and management consultancy Atkins has concluded that there would have to be 2,770 weekend closures – totalling 144,000 hours of work - on the East Coast, West Coast and Midland mainlines if it was to replace the intended capacity of HS2.
The study, which will be published on Tuesday as part of the Government's strategic business case for HS2, warns that, during a typical weekend, the journey time from London to Leeds could more than double from two hours ten minutes to more than four and a half hours.
The report, quoted by The Guardian, considers the alternatives very unattractive. "While some works could be programmed to coincide in terms of network downtime, this scale of work on the existing network would entail 14 years of weekend closures to allow the necessary upgrade works to be carried out,” the report states.
According to Robin Gisby, Network Rail's managing director of network operations, any attempt to upgrade existing lines would inevitably lead to "very heavy disruption" to services, as due to work being carried out on multiple parallel routes, the scope to use adjacent main lines for diversionary routes is also diminished.
"We saw that with the upgrade of the West Coast over the last decade,"he told the BBC Radio 4 Today programme. "If you think of the route from London through the Channel Tunnel, that used to go into Waterloo - supposing we had upgraded the line from Waterloo all the way through the middle of London commuting out to the Channel Tunnel instead of building High Speed 1 - it would have been very difficult,” he said.
"I think the same applies north of London. What we need is more fresh capacity. Doing that by cannabalising some of the existing routes don’t give you give you the long-term balance and causes considerable disruption in the meantime."
The report comes as a number of Tory MPs are about to vote against a Bill paving the way fot the project.
Transport minister Robert Goodwill said the Network Rail-Atkins study made it clear that upgrading existing lines was not viable. Costing some £20bn, according to current estimates, the upgrade would provide only a third of the capacity of the HS2.
"Spending £20 billion on upgrading the existing network isn't an alternative. The disruption that would be caused would be a nightmare. This report makes that absolutely clear," he told the Today programme.