Derailment Near Watford Junction due to landslip

[Oldddudders]

In a previous life, I recall a series of meetings about a proposed theme park up the hill at Leavesden. The promoters were keen to open a new station right by this tunnel mouth. Capacity issues on WCML fortunately killed the idea. 

[chrisf]

I've had BBC News on all morning.  There has just been an interview with what appeared to be a rescued passenger.  While most admiring of the conduct of the driver of the derailed train, she did seem to be advocating putting back the trees that have been cleared.  Not sure that I agree with her.

 

Chris

[phil-b259]

Suggestion on Twitter that a Voyager is being used to carry out the rescue of the stranded passengers.

 

https://twitter.com/NetworkRailBHM/status/776724218453061632

 

Confirmed here http://www.bbc.co.uk/news/uk-england-beds-bucks-herts-37382635

[jonny777]

That would explain the photo I saw earlier

 

 

[The Stationmaster]

Rule book module for dealing with a train accident: http://www.rssb.co.uk/rgs/rulebooks/GERT8000-M1%20Iss%203.pdf

 

More dumbing down alas - I wonder who approves this stuff let alone who writes it.  'train accident' - how blinkin' dim can you get?

 

This is how I refer to it, says it all without any Daily Mailisms -

 

PART 2 - SECTION M

Protection of Failed Trains and Obstructions on the Line

[Bruce Depot]

The cutting seems to have very steep angled sides?

Perhaps a retaining wall will end up being built here....

[The Stationmaster]

The cutting seems to have very steep angled sides?

Perhaps a retaining wall will end up being built here....

 

It has always had steep sides of course but I wonder if allowing trees to grow has partially destabilised the structure of the ground and made the cutting sides more likely to slip in heavy rain?  Does anyone know if the Watford Tunnel cuttings were prone to slips in the past?

[298]

I've had BBC News on all morning.  There has just been an interview with what appeared to be a rescued passenger.  While most admiring of the conduct of the driver of the derailed train, she did seem to be advocating putting back the trees that have been cleared.  Not sure that I agree with her.

 

Chris

She probably heard that trees slow down the path of the water and can reduce the severity of flash floods. Then again, trees can sometimes topple down the embankment, and having a group of three siblings hanging around the railway can reduce accidents, especially if two of the girls are wearing red bloomers.

[jonny777]

I'm afraid that if a large amount of water suddenly finds a quick way down a steep slope, then there is very little that can stop it.

[jonny777]

There does appear to have been a great deal of tree removal since this shot was taken a few years ago.

 

 

 

 

Mind you, there also seems to have been a lot of concreting over of the old aerodrome site since then, as well.

 

 

 

Lots of extra run-off rather than just soaking into the ground.

 

 

( Why has that second photo appeared twice? )

[Reorte]

The cutting seems to have very steep angled sides?

Perhaps a retaining wall will end up being built here....

Looks like there already is a bit of one, on the left of the photo, so I'm guessing not the first time there's been trouble at this spot?

[Nearholmer]

What the photos above don't really show is that there is a lot going on above that tunnel-portal currently.

 

I'm not entirely sure what; it's very hard to see from a passing train on the fast roads, but there is either a new structure (building?) or what I read to be a large temporary concrete silo. As I said earlier my surmise (no more than that) is that there has been stabilisation work (injecting concrete into the soil) going-on, but it could be something else entirely.

 

Kevin

[Bernard Lamb]

In a previous life, I recall a series of meetings about a proposed theme park up the hill at Leavesden. The promoters were keen to open a new station right by this tunnel mouth. Capacity issues on WCML fortunately killed the idea. 

They built it and provided a bus link from Watford Junction.

At certain times of the day the trains are packed with kids around the age of 12-13.

The stairs and doors at this station always were awkward but now it is horrendous.

Harry Potter I believe is the name of the culprit.

Bernard

[Nearholmer]

It just also struck me that Harry Potter lives on top of the tunnel - WB leavesden studio.

 

Interesting pictures of the studio "back lot" here http://wbsl.com/backlot the cutting and tunnel portal are just out of shot of a couple of these views, which show what was once an airfield runway.

 

Vast amount of development in recent years, but I can't quickly find anything about current works through the WBC planning portal.

 

K

[russ p]

Suggestion on Twitter that a Voyager is being used to carry out the rescue of the stranded passengers.

 

https://twitter.com/NetworkRailBHM/status/776724218453061632

Finally they have found a job that a voyager is suitable for!

[Paul W]

I guess the extensive tree removal from the embankments was as a result of the "leaves on the line" syndrome and in such a deep cutting the leaf fall would have had a very accumulative effect, no doubt.

 

However, going back to my O level geography from some 35 years ago, when trees are removed for this purpose on embankments this does destabilise the ground upon which they once stood, as their roots die off and rot and causes instability in the surrounding area. In many cases subsidence is a problem as the area once taken up by the deep and extensive root systems is taken up by the soil around it and is less compact and more prone to slipping.

 

As a result of the tree removal this will be why they were pumping in material to help with the stabilisation of the embankment, but maybe NR  will need to think again of the processes used as it would be a good idea to do any stabilisation work before you destabilise the area by removing the trees and bushes.

 

As said in other posts there is also alot of work going on above the area effected which would have added to the effect of the heavy rain in the area.

 

Just a good thing that no injuries were sustained or it may have given our wonderful sensationalistic  press something to get their teeth into with their  inaccurate reporting skills and over statements.

[big jim]

It just also struck me that Harry Potter lives on top of the tunnel - WB leavesden studio.

 

 

Perhaps they could use his wizardry powers to clear the tracks "desiro rerailus"

[Metr0Land]

She probably heard that trees slow down the path of the water and can reduce the severity of flash floods. Then again, trees can sometimes topple down the embankment, and having a group of three siblings hanging around the railway can reduce accidents, especially if two of the girls are wearing red bloomers.

OT perhaps but it's an urban myth that they were bloomers. They used their petticoats.

[Ian Hargrave]

It has always had steep sides of course but I wonder if allowing trees to grow has partially destabilised the structure of the ground and made the cutting sides more likely to slip in heavy rain?  Does anyone know if the Watford Tunnel cuttings were prone to slips in the past?

That's an interesting observation.Any activity with natural planting....trees,shrubs etc.is bound to affect land drainage in some way and alter water courses.Far from me to question the work done by Network Rail on the terrain in question but when someone posted that there had been some tree cutting on the embankment that slipped did make me sit up and think of a conversation I had with a local authority surveyor and quite an authority on matters arboreal a few years back.

 

Our house is situated at the top of a high bank with a steep front garden which has over the course of some 40 years has seen a variety of trees come and go....birch,poplar,conifer etc....victims of age,wind and weather.One large copper beech remains at the bottom right hand corner which receives frequent pruning because it hangs over the main road and looms a little too large.It has also looked for water with its roots inside the drain which needed remedial excavation as a result. Take it down,I ask? I was advised not because it's rooting system was considered to be holding the bank on adjoining land stable ,actually preventing collapse.I believe the main road at this point was once a cutting on the Burton -Ashby tramway,hence the steepness of the land.

I have,over many years ,restocked my front garden with shrubs,partly for ornamental reasons,but also for maintaining the integrity of the land structure to prevent slippage with their rooting systems.This is noticeable in a prolonged dry spell when the clay soil dries out and cracks appear on the surface.

Again with regard to trees affecting the landscape,we live on the immediate edge of The National Forest.Locally ,land drainage has significantly altered as a result,people finding springs appearing in their back gardens where none existed before.

Yes,trees when they fall cause significant danger and damage....especially when they are close to busy rail tracks....but the whole picture is too complex for a judgement call.No one could have envisaged such a biblical deluge.Thank God it all ended without a tragedy?Who'd be a Network Rail engineer ?

[The Stationmaster]

I guess the extensive tree removal from the embankments was as a result of the "leaves on the line" syndrome and in such a deep cutting the leaf fall would have had a very accumulative effect, no doubt.

 

However, going back to my O level geography from some 35 years ago, when trees are removed for this purpose on embankments this does destabilise the ground upon which they once stood, as their roots die off and rot and causes instability in the surrounding area. In many cases subsidence is a problem as the area once taken up by the deep and extensive root systems is taken up by the soil around it and is less compact and more prone to slipping.

 

As a result of the tree removal this will be why they were pumping in material to help with the stabilisation of the embankment, but maybe NR  will need to think again of the processes used as it would be a good idea to do any stabilisation work before you destabilise the area by removing the trees and bushes.

 

As said in other posts there is also alot of work going on above the area effected which would have added to the effect of the heavy rain in the area.

 

Just a good thing that no injuries were sustained or it may have given our wonderful sensationalistic  press something to get their teeth into with their  inaccurate reporting skills and over statements.

 

The problem stems really from letting the trees grow in the first place.  Those cuttings used not to be wooded on the sides - probably some at the top but on the slopes nothing more than a few bushes.  But total lack of attention in the past 20 odd years means trees have got established and their root systems have penetrated the banks thus when the trees are got rid of you get the sort of problems you describe.  All down to an extended period of poor stewardship which, , regrettably, started in BR times although it has got far worse since - leading to leaf fall problems as well of course.

 

I found it quite illuminating on the Western when in the mid 1980s we began to suffer from increasing leaf fall problems and began to catch up the Southern in that respect.  When you applied a bit of logic it became very obvious what was happening - with the end of steam bank burning had ceased thus trees and shrubs began to grow unhindered.  Mid 1980s and trees approaching 20 years old and becoming mature and shedding ever more leaves every autumn - and we started getting into worse and more widespread wheelslide and adhesion problems.  Easy answer - chop down the trees.

[EdChap]

Amazing piece of reporting by a passenger on the Daily Fail website:

 

 

Radio reporter Sarah Lowther, who was on the derailed train, said two trains were 'kissing each other' in a tunnel.

 

She spoke of a 'Dunkirk spirit' on board as passengers helped one another, but said she was 'worried' about the driver, who had a bad back after the crash.

 

Speaking to Morning Money radio, she said: 'The trees were taken down from the side of the rail line last year. Trees have roots, roots hold the mud ... The mud had nothing to cling on to.

 

'It was the first time I've actually flown on a train; when we came off the tracks I assumed the brace position.

 

'Everyone is looking after each other with water and sugar but we're worried about our driver.'

Edwin C.

[298]

OT perhaps but it's an urban myth that they were bloomers. They used their petticoats.

 

 

Thanks for the clarification. I wasn't in a position to Google it.

 

Amazing piece of reporting by a passenger on the Daily Fail website:

'Everyone is looking after each other with water and sugar but we're worried about our driver.'

 

Edwin C.

Lots of Bees on the train...?

[woodenhead]

Perhaps they could use his wizardry powers to clear the tracks "desiro rerailus"

You have to be careful with magic, it can all go badly wrong.  By all accounts Ron's attempts with that spell resulted in the spacious 350 turning into an ugly Voyager.

[The Stationmaster]

Amazing piece of reporting by a passenger on the Daily Fail website:

 

 

Radio reporter Sarah Lowther, who was on the derailed train, said two trains were 'kissing each other' in a tunnel.

 

She spoke of a 'Dunkirk spirit' on board as passengers helped one another, but said she was 'worried' about the driver, who had a bad back after the crash.

 

Speaking to Morning Money radio, she said: 'The trees were taken down from the side of the rail line last year. Trees have roots, roots hold the mud ... The mud had nothing to cling on to.

 

'It was the first time I've actually flown on a train; when we came off the tracks I assumed the brace position.

 

'Everyone is looking after each other with water and sugar but we're worried about our driver.'

Edwin C.

 

So she's very clearly is not a trained journalist - that sort of garbage writing is a long way from the way things are taught on the really good journalism courses.  Mind you with rubbish like that maybe she's after a job on the 'Daily Wail' - she'd fit in beautifully there.

[Silver Sidelines]

Having carried out and published research into ground movements due to vegetation I can confirm that trees, particularly Alder, Willow and Poplar are very efficient pumps and will dry the ground out quite splendidly.  On clay soils this often results in serious damage to rigid structures like house foundations, concrete roads and cast iron / asbestos water and gas pipes.  On one site in Swindon we measured around 300mm surface movement annually.

 

Cut down the trees and the ground will begin to 'wet up'.  I believe that a lot of housing somewhere around Crawley was built on sites previously covered with birch trees.  There was no time delay between cutting down the trees and building the houses which resulted in some quite serious structural problems where houses 'burst' apart.

 

Yes tree roots will act as a natural geotextile and hold the ground in place.

 

A lot of the cuttings to the north of London are 'over steep'.  This could be because  they are in rock.  However a lot of the old railway and canal cuttings were stablised by filling the cuttings with straw bales which were then fired to bake the ground.  Now it does occur to me that in the days gone by with steam trains it was not unusual for the vegetation to be burnt on a regular basis - perhaps adding to the baking process?

 

Certainly things have gotten very damp lately and there is perhaps a need to readjust and reappraise some of these structures.

 

Regards

 

Ray