Landslips - more common now, or have we just noticed?

[whole diary]

[grahame]

I've been looking to start a general thread about landslips ... are we seeing more of them, or just hearing more about them? Have we just noticed something that's always been there with the aeful accident in Scotland? I did a search for landslip on the forum ...

Matched 326 posts in 122 threads

And came across another landslip - this time on a well known road - at BBC^» (British Broadcasting Corporation - home page) Scotland

The A83 runs for almost 100 miles from Loch Lomond to Campbeltown, at the foot of the Kintyre peninsula. But there is one section, near the Rest and Be Thankful, which has become infamous for landslips, closures and long diversions.

James MacDonald and his family watched in horror as 30,000 tonnes of rock and mud churned its way down the side of the mountain towards them.

He later described the landslide as "boiling with gyrations and spurts of water" and the noise of an "indescribable roar - the roar of a mountain in torment".

The road near Arrochar became impassable as the debris hurtled down, and flooded the Glen Croe valley below.

But this landslide is not the one that has closed the mountain road for the last three weeks; nor was it then known as the A83.

MacDonald's testimony is from 1913.

[Electric train]

I've been looking to start a general thread about landslips ... are we seeing more of them, or just hearing more about them? Have we just noticed something that's always been there with the aeful accident in Scotland? I did a search for landslip on the forum ...

Matched 326 posts in 122 threads

And came across another landslip - this time on a well known road - at BBC^» (British Broadcasting Corporation - home page) Scotland

The A83 runs for almost 100 miles from Loch Lomond to Campbeltown, at the foot of the Kintyre peninsula. But there is one section, near the Rest and Be Thankful, which has become infamous for landslips, closures and long diversions.

James MacDonald and his family watched in horror as 30,000 tonnes of rock and mud churned its way down the side of the mountain towards them.

He later described the landslide as "boiling with gyrations and spurts of water" and the noise of an "indescribable roar - the roar of a mountain in torment".

The road near Arrochar became impassable as the debris hurtled down, and flooded the Glen Croe valley below.

But this landslide is not the one that has closed the mountain road for the last three weeks; nor was it then known as the A83.

MacDonald's testimony is from 1913.

The NR^» (Network Rail - home page) Route / Regional Geotech asset managers have had significant funding through CP5^▸ (Control Period 5 - the five year period between 2014 and 2019) and in CP6^▸ (Control Period 6 - The five year period between 2019 and 2024) for drainage and earthworks stabilisation and the one no one likes de-vegetation

Drainage clearance and maintenance has been increased, but where there has been a collapse access to excavate to repair / replace can be challenging.  Major earthworks are expensive and have a long lead time for design and in some cases a 2 week blockade is needed these have to be planned years in advanced.

[stuving]

What you want is statistics! NR^» (Network Rail - home page) must have loads of historical numbers, of landslips (by type), of which those blocking the track, of which those causing derailment, of which those causing injury or death. I can't find that, but NR's site has a report for 2018 on "Earthworks Technical Strategy". That's a plan - but not as woolly as most; it would be worth looking at for technical content, and in particular for its coverage of current and future monitoring systems. It has few data that I can see, but does list earthwork failures by CP and severity, from which "potentiall high consequence earthwork failures" and "earthwork attributable derailments":

       PHCEF   EAD
CP1:  n/a       7
CP2:  n/a       8
CP3:  41        8
CP4^▸ (Control Period 4 - the five year period between 2009 and 2014):  32        8
CP5^▸ (Control Period 5 - the five year period between 2014 and 2019):  18        2   (4 years only)

I tried looking wider, for RSSB^▸ (Rail Safety and Standards Board) research, but finding anything in Spark (the RSSB library) has got even more difficult since they "improved" its web design. I did find one RAIB^▸ (Rail Accident Investigation Branch) special report from 2008 into "Network Rail’s Management of Existing Earthworks", with a short section about trends.This had very limited data (for 2003-2008), and reading numbers by eye off their graph gives the following counts for "earthwork failures" (a much bigger category than just landslips). These are also broken down by type, again only for that short period, and I've picked out the biggest category - "cutting slip" and added that:
         all falures  c/slip
2003/4:  45          n/a
2004/5:  55          22
2005/6:  39          14
2006/7:  88          34
2007/8:  107        36

This is part of the same section:

58 In the period covered by this data, train derailments attributed to earthwork failure were:
 1 in 2003/4 – rock fall;
 1 in 2004/5 – embankment slip;
 2 in 2005/6 – 1 cutting slip and 1 cutting washout;
 3 in 2006/7 – 1 cutting washout and 2 cutting slips; and
 0 in 2007/8.

59 The last fatality related to an earthwork failure was in 1995, when a derailment occurred on the Settle and Carlisle line and a member of the traincrew died in a subsequent collision with another train. Her Majesty’s Railway Inspectorate (HMRI^▸ (Her Majesty's Railway Inspectorate)), at that time part of the Health & Safety Executive, published a report into the accident in October 1997, which recorded the actions taken, none of which were related to infrastructure or earthworks, and made no further recommendations. It has proved difficult to establish the previous attributable fatality, but it was a considerable time ago, and may have been before 1940.

Sadly that record now reads quite differently - though it's not something where a "trend" would be meaningful.

[grahame]

Many thanks for researching this one.

I would agree that the figures for deaths are frankly far too small to show a trend, and thank goodness they are. We are not in a pattern such as before block signalling 170 years ago, pre-continuous-brakes 150 years ago, or gas lit carriages which must be 100 years ago.

Climate change and more extreme weather may be increasing risk (like it may be increasing other elements such as line side vegetation growth) but it's being monitored and managed (?) - both to reduce failures, and to trap failures before they have catastrophic consequences. Whether initial build / rebuild needs to be to a more robust standard is also a consideration; what standards and allowances for a more extreme climate are being made on HS2^▸ (The next High Speed line(s))?

[Electric train]

Whether initial build / rebuild needs to be to a more robust standard is also a consideration; what standards and allowances for a more extreme climate are being made on HS2^▸ (The next High Speed line(s))?

From my experience (and that as an electrification engineer    ) of bring into service a new piece of infrastructure the climate impacts are run as models in software, if i recall correctly, a storm severity of a once in 50 year, once in 100 years events, and I believe they can run longer. 

These models form part of an overall risk assessment for all of the assets about operational recovery and systems damage limitation as the result of a once in 50 and 100 year events, and not about running trains during the event although this all feeds into the operational guidance of the assets.


Railway engineering has move a long way since our Victorian forebears built the majority of the current railway infrastructure

[paul7575]

Relatively minor damage with running sand, chalk, soil and vegetation etc adjacent to tunnel portals, which luckily didn’t cause major accidents.  I can think of at least four from recent memory.  Obviously Wallers Ash last week, Guildford Sand tunnel was a couple of years ago, Gillingham Tunnel was a few years ago. 

At Watford tunnel we had a couple of 350s side swipe at a fair speed, it could have been far worse.

Although I’m no expert, there does seem to be a noticeable danger area at many tunnel portals, just where the cutting sides on the approaches are getting more and more vertical, you’ll see quite a few, like at Wallers Ash, already have concrete and steel “fences” in place to catch run off around the portal area.  I wonder if those safety structures will have to be made systematically bigger and stronger, and even longer?  That way any slips could be diverted alongside rather than across the tracks.

(Some years ago I saw a very similar failure mode at Braunston Tunnel on the Grand Union canal, a mainly sand embankment slipped immediately outside the west portal.  Not quite the same hazard to a canal boat, but it had half blocked the canal overnight.)

Noting the above point about Victorian forebears, I suspect the first railway tunnel portal designs closely followed the canal builder’s methods?

Paul

[Surrey 455]

Relatively minor damage with running sand, chalk, soil and vegetation etc adjacent to tunnel portals, which luckily didn’t cause major accidents.  I can think of at least four from recent memory.  Obviously Wallers Ash last week, Guildford Sand tunnel was a couple of years ago, Gillingham Tunnel was a few years ago. 

That was in December 2019, 8 months ago .

[paul7575]

Relatively minor damage with running sand, chalk, soil and vegetation etc adjacent to tunnel portals, which luckily didn’t cause major accidents.  I can think of at least four from recent memory.  Obviously Wallers Ash last week, Guildford Sand tunnel was a couple of years ago, Gillingham Tunnel was a few years ago. 

That was in December 2019, 8 months ago .

Thanks.  Seems longer for some reason...

[CyclingSid]

Meanwhile on the roads it is not so easy to solve the problems https://www.bbc.co.uk/news/uk-scotland-53922077
and in some cases you have to admit defeat https://en.wikipedia.org/wiki/A625_road#Mam_Tor_road

[IndustryInsider]

I remember cycling the Mam Tor road when I was much younger, as it was closed to road traffic but you could still cycle along it.  Though I can’t remember whether you were supposed to or not!