Second report warns HS2 route raises risk of train derailments
GOVERNMENT advisers have warned that “many locations” along the HS2 rail line have unstable soil putting highspeed trains at risk of derailment.
In a damning new study of the HS2 route, scientists from the British Geological Survey (BGS) named three specific sections of the line as having “very soft fine soils” which are vulnerable to “track and ground displacement” under the pressure of trains travelling at the speeds planned for HS2.
The study echoes other research commissioned by HS2, reported in last week’s Sunday Telegraph, which warned of “significant issues” with track “instability,” and demanded major changes to make the route safe.
HS2 is intended to run at 225mph in routine service, faster than any other rail-based trains in the world, and rising to 250mph after a few years.
But the BGS scientists, David Gunn, Gareth Williams, Holger Kessler and Stephen Thorpe, warn these speeds could generate waves that can cause “track and ground displacements.”
They add that “these characteristics are likely to occur at many locations” along the HS2 route, with three sections – around Perivale, in west London, Aylesbury, Bucks and Hampton-in-Arden, just south of Birmingham – being at particular risk.
The BGS is the public-sector body responsible for advising the Government on all aspects of geoscience.
The study is the latest blow to HS2, which has its third reading debate in the Commons later this week. The £50billion scheme already faces a third National Audit Office inquiry.
The BGS study only covers the first phase of HS2, linking London and Birmingham. But the second phase – extending the route to Manchester – passes directly over a second area of highly unstable ground, the salt-mining district of Cheshire.
Over several centuries, enormous caverns have been dug out just beneath the surface, leading to frequent ground collapses. Many buildings have had to be shored up against subsidence. Commercial mining continues today.
“Coming out of the tunnel under Crewe the proposed HS2 route is directly above the active salt mine,” said Ros Todhunter, a local geologist, He also warned of hollows along the route near Winsford and Middlewich, In the HS2sponsored research released last week, Prof Peter Woodward, one of the world’s leading experts in the geo-engineering of railways, said that ballasted track of the kind to be used by HS2 “may not be able to adequately retain the track geometry” at speeds of 225mph.
He said that “embankment instability, particularly over poor soils such as collapsible soils, will generate significant issues.” Around 107 miles of the route, about a third of the total, will run on embankments.
To avoid the danger, HS2 trains may have to be slowed on several stretches or there may need to be massive works to stiffen the ground, potentially adding billions of pounds to its cost.
HS2 needs to run at 225mph if it is to meet its ambitious business case. It claims it will be able to run up to 18 trains an hour – one every three minutes 20 seconds – along the core route.
Hilary Wharf, director of the HS2 Action Alliance, said: “What is clear is that nobody knows how to design HS2 to achieve its 225mph design speed safely. If the solution is left to an operational fix, trains will clearly have to run slower and the already dire economic case collapses entirely.”
A spokesman for HS2 has said detailed designs would be based on specific “ground investigation” work carried out as they get access to the whole route.
‘Trains will clearly have to run slower and the already dire economic case collapses entirely’