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Pandora

Tonbridge to Redhill Bankslip December 2019

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There’s a road at the bottom of the slip...

 

how come that can’t be used for access, rather than ploughing through a field, digging out an embankment etc.

Though admittedly from Google maps, it looks like a posh neighbour with a private grass field airstrip... maybe reduced noise ?

 

As an aside.. what if the landowner says No ?

Edited by adb968008

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8 hours ago, Pandora said:

Recalling a conversation with a retired Railway Civil Engineer formerly involved with restoring a major  railway bridge,  " Todays Graduates just don't know how to go about making things anymore" I am sure the said engineer would have lifted out the panels and dropped a 1000 tons of ballast into the  voids on the line, relaid the panels and the service would be running with a 10 mph TSR until a better solution was devised

 

Thats all very well in theory but (1) dumping fill onto a slip that is still moving or unstable is very likely to start it slipping again and (2) you still need a lengthy further closure to sort it out.

 

were it something like the BML then the amount of disruption the closure would cause means that a ‘temporary’ repair becomes more important - but on a cross country secondary service like the Redhill to Tonbridgd Line, busses and alternative routes will be able to cope just fine.

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5 minutes ago, EmporiaSub said:

Never mind about bringing everything in to the site, the other issue is that for the next week or so, the replacement rail service is a bus between Redhill and Tonbridge.....

No doubt because NR require the use of one of their Mobile Operations Managers to operate the ground frame at Edenbridge, whereas in the past it would have been done from Edenbridge signal box.

 

Under normal circumstances that ground frame only gets used for engineering works so it’s entirely appropriate for it not be signalled.

 

Regrettably this was standard BR policy - adding remote signalling controls costs money so if emergency crossovers were retained then a locally operated ground frame was the best choice

 

That said these days the tendency is to actually fully signal such crossovers so they may be operated remotely. Whiteness the Arun Valley Line where the unsignalled “emergency” mechanical crossovers were upgraded  so they could be used to turn back stuff without needing a MOM.

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On 25/12/2019 at 22:07, phil-b259 said:

As I understand it the earth is still moving!

 

Until it stops, NR are unable to plan remedial works properly.

20 hours ago, jim.snowdon said:

Very different from the days of the traditional railway, when labour was still relatively cheap and plentiful, and trainloads of replacement fill would have been taken to site using the other line and tipped or, more likely, shovelled out by hand. It probably wasn't as good a job, but the emphasis was on using practical expertise to get the railway open again rather than the minimal risk text book approach taken these days using road:rail plant and road access.

 

Jim

And sometimes it worked and has stood the test of time for more than 50 years.  There was a big slip on the Greenford branch back in 1967 and several thousand tons of material plus a couple of Grampus wagons went into that one and it hasn't moved since (yet).  Similarly there was one just west of where Twyford station car park is now  which was a consequence of soft subsoil around one of the tributaries of the Loddon.  (The whole are is soft underneath for quite a distance apparently which would mean a multi-storey car park on the site could be mega expensive.). Anyway there was about 500 tons of spoil from Paddington layout alterations and elsewhere which went into that every Saturday night for a couple of months and it too hasn't moved since despite the state of the subsoil beneath the embankment.

 

So sometimes the old methods worked.

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1 hour ago, adb968008 said:

There’s a road at the bottom of the slip...

 

how come that can’t be used for access, rather than ploughing through a field, digging out an embankment etc.

Though admittedly from Google maps, it looks like a posh neighbour with a private grass field airstrip... maybe reduced noise ?

 

As an aside.. what if the landowner says No ?

 

Yes, I wondered about that too. If the line is closed, and closed for some time, why not use the trackbed for access, lifting the track if necessary?

 

Still amazed at some of the closure times quoted, particularly for a passenger line. I would have thought that this sort of event would have been an "all hands on deck, working around the clock to get the line open again" process, but obviously not.

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Although not connected its interesting that the timing of this incident is very similar to the landslip that occurred just outside Dover on the mainline towards Folkestone back in December 2015.

 

Some people thought that the line would be closed for good due to the geological features between Dover and Folkestone but Network Rail got stuck into it and nine months later (three months earlier than expected) the line was reopened.

 

Keith

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Being doing a bit of looking at the site on Google Earth historic photos, Old Maps, the British Geological Survey and a few matters from my own knowledge of Engineering tips down that way, which can explain why it will take so long and why the old method of just tipping earth will not work at this site.

  1. The River Eden runs close (less than 20m) to the slip site (the river culvert is just east of the slip).  Erosion by the flooded river may have been a cause, in which case access to the northern side of the toe of the embankment is going to be necessary to effect repairs and probably install bank protection measures.  Indiscriminate tipping could cause a blockage of the river, which would lead to all sorts of problems.
  2. The embankment, built some 175 years ago, is almost certainly built of loose tipped Weald Clay from the nearby cuttings, sitting on unprepared silt and clay alluvium built at angle of repose with no compaction (that's just how they did things back in the 1840s).
  3. The embankment is some 10m high, with side slopes of about 1 (vertical) to 1.7 (horizontal).  That is pretty steep for an embankment made of Weald Clay.  I am surprised it has stood up as long as it has.  This material will loose strength as it shears, so continued tipping on the top without removal of the shear plane or building a large toe buttress will just lead to an awful lot of movement sideways at the bottom, potentially damaging the river culvert.
  4. Not surprisingly, it looks from the historic Google Earth photos as though there was a major failure of the south side of the embankment in 2011/12 100m east of the current failure .  The repairs for that appear to have involved adding a fillet of fill and flattening the bank to about 1 (v) in 3 (h), a much more reliable gradient for a bank built of Weald Clay.  A lot of drainage also appears to have been installed.  The area of this failure can be seen on the current Google Earth photo as it is the area lacking trees (as a matter of interest, the Network Rail air photo with the arrows on looks to be from c2009, so does not show this slip).  This history makes it unwise to just go and tip without thorough investigation to obtain data to design the repair works.  Getting such testing done requires months.
  5. Of interest (considering the debate on this subject) mature trees were growing on the embankment in 1940.
  6. These days, you cannot just source fill from anywhere and certainly not from a site like Paddington (or any other major) Station which is likely to contain polluted material from centuries of railway operations.  The Environment Agency will insist any imported fill to a site like this is inert.
Edited by eastglosmog
Added a bit extra
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Arriving at Tonbridge this morning, the guard announced that passengers for Gatwick should change there - but with no mention of the line being closed. Has nobody told him?

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50 minutes ago, eastglosmog said:
  1. ...These days, you cannot just source fill from anywhere and certainly not from a site like Paddington (or any other major) Station which is likely to contain polluted material from centuries of railway operations.  The Environment Agency will insist any imported fill to a site like this is inert.

The Environment Agency should get over itself at times.

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23 minutes ago, spikey said:

The Environment Agency should get over itself at times.

They are just applying the law as passed by Parliament to prevent pollution of water courses and water supplies.  While I agree they can be very pettifogging at times, you would not want the unpleasant things that can be found in many old industrial sites (including beneath major railway stations) to be spread indiscriminately around the countryside.

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7 hours ago, EmporiaSub said:

Never mind about bringing everything in to the site, the other issue is that for the next week or so, the replacement rail service is a bus between Redhill and Tonbridge.....

No doubt because NR require the use of one of their Mobile Operations Managers to operate the ground frame at Edenbridge, whereas in the past it would have been done from Edenbridge signal box.

 

 

Having travelled on this line line at peak times, the number of ordinary passengers only half fills a 4 car 377 unit. A rail replacement bus service is therefore well able to cope with the number of travellers.

 

There is a large amount of schools traffic from Edenbridge and intermediate stations heading for schools in Tonbridge - but of course they are on Holiday this week so that is a consideration.

 

I fully expect the rail service between Tonbridge and Edenbridge to be resumed when the schools go back after the Christmas break.

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7 hours ago, EmporiaSub said:

Never mind about bringing everything in to the site, the other issue is that for the next week or so, the replacement rail service is a bus between Redhill and Tonbridge.....

No doubt because NR require the use of one of their Mobile Operations Managers to operate the ground frame at Edenbridge, whereas in the past it would have been done from Edenbridge signal box.

 

 

Having travelled on this line line at peak times, the number of ordinary passengers only half fills a 4 car 377 unit. A rail replacement bus service is therefore well able to cope with the number of travellers.

 

There is a large amount of schools traffic from Edenbridge and intermediate stations heading for schools in Tonbridge - but of course they are on Holiday this week so that is a consideration.

 

I fully expect the rail service between Tonbridge and Edenbridge to be resumed when the schools go back after the Christmas break.

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50 minutes ago, phil-b259 said:

 

 

Having travelled on this line line at peak times, the number of ordinary passengers only half fills a 4 car 377 unit. A rail replacement bus service is therefore well able to cope with the number of travellers.

 

There is a large amount of schools traffic from Edenbridge and intermediate stations heading for schools in Tonbridge - but of course they are on Holiday this week so that is a consideration.

 

I fully expect the rail service between Tonbridge and Edenbridge to be resumed when the schools go back after the Christmas break.


As a recently retired BR / TOC Operations Manager, I am aware that in the fragmented industry of today, what is operationally convenient is all too often the only practical method of working.

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Is that stranded 377 going to be dedicated, or will they run 5zXX  via SE lines on a daily basis ?

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54 minutes ago, adb968008 said:

Is that stranded 377 going to be dedicated, or will they run 5zXX  via SE lines on a daily basis ?

 

I would imagine a unit will be ‘dedicated’ to the shuttle service - but swapped with another via London Bridge when maintenance is due.

 

Of course Southern could always try and hire a SE unit and crew - SE are fairly frequent visitors to the line because it forms a diversionary route for Hastings trains when the route via Sevenoaks is shut.

 

On a recent occasion I had to catch a lift from Bletchingly tunnel to Godstone and although the unit was a Southern one,  the driver + guard were wearing SE uniform suggesting a degree of co-operation between franchises (which are after all both operated by GoVia)

 

Edited by phil-b259
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11 hours ago, adb968008 said:

As an aside.. what if the landowner says No ?

 

In such situation NR can go through the courts to get access - and as with electricity, gas, water, telecoms or fuel pipeline infrastructure operators, ‘emergency repair’ applications will be dealt with quickly.

 

However even then there is an obligation on the infrastructure provider to try and minimise the disruption - which could well include asking for access in such a way that it doesn’t use somebody’s private driveway or passes close to their house when other options (like a longer temporary roadway across fields away from property) are available.

 

If, on the other hand if the access is required for a ‘planned’ job e.g. NR has decided to be proactive and undertake works BEFORE anything drastic happens then the application will be processed much more slowly and the hurdles NR need to go through to gain access are harder.

Edited by phil-b259
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On 25/12/2019 at 20:15, russ p said:

What's wrong with the other road?

I think its fairly obvious from the pics.

Edited by rab
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Some Redhill/Tonbridge services use South Eastern crew but utilising Southern 377's and running with a guard whereas if it is a Southern crew its DOO with an OBS.

 

There are a couple of 377's with South Eastern that are theirs but still in Southern colours, could use one of those I suppose. 

 

Is any freight still booked via this route?

 

I notice that GBRf have shifted their Class 73 top and tailed snow clearing trains to Horsham.

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The morning Purley empty stone train usually goes via Redhill and Tonbridge so will be interested in which way they send it whilst the line is blocked

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18 hours ago, spikey said:

The Environment Agency should get over itself at times.

Very true.  interestingly in recent years we have had several lots of work in our area involving trenching associated with new gas mains and water pipes and now broadband cable.  Every time excavations have been carried out the spoil removed had  been taken away (no doubt involving a tipping licence and fee) and fresh material to meet the Council's spec has been used to backfill the holes after the underground work has been completed.  Our road is largely built on an area of gravel beds with some clay and a lot of sub chalk.  Back in the early 1960s the previously unmade road was surfaced, involving adding additional gravel material and  hoggin before the tarmac was laid onto the well rolled sub-material.  But when that was dug out it was taken away and new material provided - all at extra expense to basically achieve nothing new.

 

That of course is a small example but it shows exactly what can happen - money wasted simply to backfill holes in the road.

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Apologies if it was mentioned here already but the EA (SEPA in Scotland) seem to be adding to the increasing risk of flooding/saturation in many areas.

Where once many rivers/streams/channels etc were periodically dredged to keep the surrounding land clear, they seem to have banned this to avoid disturbing 'natural habitats'.

There was a case in Scotland a couple of years ago (non-railway) where regular bad flooding affected a village/small town - the main road and some property were directly affected everytime there was heavy rainfall. A local farmer took it upon himself to dredge out a burn running through his land, which largely cured the worst of the flooding, but found himself being prosecuted by SEPA for the unauthorised damage done to the natural habitat in and around the burn.

In these days of seemingly increasing flooding (or flood risk), the waterways which once ensured the water flowed safely away are gradually silting/blocking up to the point that even moderate rainfall is causing problems in areas which never used to suffer.

Edited by keefer
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My feelings about The Environment Agency stem from having once been involved on the fringes of a long-running stand-off between them, Natural England, English Heritage and a Great Crested Newt.  Yes, one Great Crested Newt.  The amount of time and money spent on that farce was beyond belief, when the whole matter could easily have been resolved by the application of common sense and a few sticklebacks (locally-sourced, of course ...).

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Got another potentially nasty landslip now, south of Lingfield on the East Grinstead line.

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28 minutes ago, John M Upton said:

Got another potentially nasty landslip now, south of Lingfield on the East Grinstead line.

I think Dr Beeching commuted from E Grinstead. In those days he would have been able to catch a train across to Three Bridges, thence to London. Not now, though. 

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