Anderson's Piano

[Dagworth]

 

[5BarVT]

Thank you.  Haven’t seen them in closeup for about 29 years (for about 11 months they were ‘mine’).

As I recall, they don’t actually need the wire to break to detect a boulder.  I can’t quote the detail, but I think each ‘fence’ wire is connected to a complicated mechanical structure opposite the signals such that if a wire is pulled far enough it will allow a counterweight to fall which releases the wire holding the signal off.  A wire breaking has the same effect.  As does sheep getting their horns stuck in the wires and pulling to get them out.

One of the advantages the semaphore system has is that it is instantaneous advice to the driver.  The listening fibres mentioned can detect boulders but the problem is getting that information back to the right driver.  The radio system is open channel so that every driver hears every message (and that is part of the signalling system safety justification) but sending an emergency stop message to every driver and expecting all bar one to ignore it is not a good safety system.  And that’s assuming the radio isn’t in use for some other signalling reason at the time the boulder strikes.

Paul.

See later post - it looks like I’m wrong about pulled wires and which department owned the system.

 

Edited March 8, 2022 by 5BarVT
Updated info.

[SHMD]

Shouldn't the signals be yellow (distant) rather than red (stop) as the driver is instructed to proceed past them - at caution - automatically?

 

 

Kev.

[benachie]

The C & O in the South West of Scotland??   He needs a geography lesson.

[The Stationmaster]

39 minutes ago, SHMD said:

Shouldn't the signals be yellow (distant) rather than red (stop) as the driver is instructed to proceed past them - at caution - automatically?

 

 

Kev.

I'm a bit puzzled by that comment. A distant signal at caution won't stop a train - it simply tells the Driver that the next stop signal in advance is to be regarded as being at danger.  A stop signal should stop a train  (even if in this case the Driver might run by  it depending on sighting distance).  And in the event of any stop signal being at danger a Driver can be instructed to pass it .  There are no doubt some special instructions in relation to the avalanche signal which might authorise a Driver to pass them at danger proceeding cautiously prepared to stop short of an obstruction?

[5BarVT]

1 hour ago, The Stationmaster said:

There are no doubt some special instructions in relation to the avalanche signal which might authorise a Driver to pass them at danger proceeding cautiously prepared to stop short of an obstruction?

Indeed there are.  From the Network Rail Scottish Sectional Appendix.  (SC9 page 59 (p633 of the full document) search Network Rail NESA and scroll down to downloadable pdf.)
Pass of Brander - Automatic stone signals - Between the 51 3 ⁄4 and 56 mile posts in the Pass of Brander, 16 automatic stone signals are erected on the South or loch side, and one near the 54 mile post on the North or hill side of the line, at irregular distances from each other, and at points where the best view can be obtained of them from either direction. All these signal posts carry an Up and a Down arm, with the exception of the one at the East end which carries a Down arm only, and the one at the West end which carries an Up arm only. The signals are connected by a number of wires forming a screen which runs along the top of the railway slope on the hill side of the line, and so long as the screen wires remain intact, the signals remain clear; but in the event of a stone falling from the mountain and one or more wires being broken; Up and Down signals go to danger. Every alternate wire passes the first signal post and is connected with the second signal post, and when a driver sights a signal at danger he must reduce speed and proceed cautiously in accordance with the Rule Book, Module S5, until a second clear signal is reached - as there may be one clear signal between two danger ones - or until the last special signal for the falling stones is passed. He must also inform the signaller at Banavie signalling centre by radio that a stone signal is at danger.
Dated: 02/12/06

 

Looks like I might be wrong about the operation as the instruction says ‘broken wires’.

The wording is identical to the 1960 ScR West appendix, other than the latter advising that alarms go to pway section gangers and lamps are the responsibility of S&T (in place of ‘report to Banavie’ above).   Looks like I might be wrong about responsibility for them too!

 

Paul.
 

[Michael Hodgson]

If it's not too heretical an idea to tinker with it, it could be presumably be modernised a little by fitting a signal repeater circuit which reads through all of the semaphore arms, which could in turn operate (approach-lit) colour light distants to give slightly better warning.  This would of course require a power supply - but I expect it already has electric lamps, and there's what I assume to be a hydro-electric power station in the valley anyway.  Whether the benefit would be cost-justified is perhaps another matter.

[ejstubbs]

26 minutes ago, Michael Hodgson said:

there's what I assume to be a hydro-electric power station in the valley

 

The power station is the other side of the A85 from the railway, pretty much right next to Falls of Cruachan station, on the shore of Loch Awe.  It's actually a pumped-storage hydroelectric power station, using water which is pumped nearly 400m up to the Cruachan Reservoir in the corrie below Ben Cruachan (imaginatively name Choire Cruachan) during periods of low electricity demand.  As such, it's one of only four pumped-storage hydroelectric power stations currently operating in the UK (the others being Foyers above Loch Ness, and Dinorwig and Ffestiniog in Wales).

Edited March 8, 2022 by ejstubbs

[5BarVT]

49 minutes ago, Michael Hodgson said:

If it's not too heretical an idea to tinker with it, it could be presumably be modernised a little by fitting a signal repeater circuit which reads through all of the semaphore arms, which could in turn operate (approach-lit) colour light distants to give slightly better warning.  This would of course require a power supply - but I expect it already has electric lamps, and there's what I assume to be a hydro-electric power station in the valley anyway.  Whether the benefit would be cost-justified is perhaps another matter.

Not heretical, but not quite as simple as that!!!  It’s over about 4 miles so to warn a train at the start to proceed at caution for 4 miles isn’t what’s wanted.  It’s a series of interlinked local warnings using stop arms as an indicator (but not as a signal).  Line speed is 45 so about 300m braking give or take, hence the irregular spacing of ‘signals’ where they can be best seen.  A sort of ‘stop and proceed on sight’.

Ingenious for the time, maintenance heavy, but nothing better to supersede it (yet!).

And NR are trying to find something else that works.
Another ‘issue’ is that it’s trying to detect big rocks that could damage/derail a train without getting false alarms for every little rock that tumbles by, or leaves, or, or, !  So I don’t think a series of light beams could do it either.
Paul.

[iands]

3 minutes ago, 5BarVT said:

 

Ingenious for the time, maintenance heavy, but nothing better to supersede it (yet!). And NR are trying to find something else that works.
 

It will be interesting so to see what development an "interface" with ERTMS would look like, if that section of line ever gets the same treatment as the Cambrian line. I'm sure other "railway operators" on the continent are possibly looking at similar issues (ERTMS interface), as several other countries have higher mountains than the UK and presumably their "rock fall" issues are potentially greater/more frequent than ours. I guess a "solution" (ERTMS interface) would perhaps benefit an interface with the "airport trip wires" as they serve a similar purpose.

Just my observations on an interface issue with a decades-old tried-and-tested system with modern state-of-the-art technology to give at least the same level of warning/safety and reliability of operation.

[Michael Hodgson]

4 minutes ago, 5BarVT said:

So I don’t think a series of light beams could do it either.

Paul.

They would probably be triggered by animals!

 

I appreciate your point about not wanting to cause unduly early braking, but a circuit based on arm proving contacts could indicate which stop signal has been tiggered, and operate a theatre type indicator to advise the approaching driver know which signal is the first he will find at danger - say Yellow + 7.  It could also transmit a message to S&T, rather than wait for the first driver to radio in, which should at least mean earlier repair.

[Michael Hodgson]

4 minutes ago, iands said:

I'm sure other "railway operators" on the continent are possibly looking at similar issues (ERTMS interface), as several other countries have higher mountains than the UK and presumably their "rock fall" issues are potentially greater/more frequent than ours. I guess a "solution" (ERTMS interface) would perhaps benefit an interface with the "airport trip wires" as they serve a similar purpose.

I think those countries usually tackle the problem by building avalanche shelters, no doubt at great expense.

 

I thought aiport trips were basically a "panic button" in the control tower at RAF Valley which swtiches on a normally dark colour light, a bit like having a SPADI ?

[iands]

2 minutes ago, Michael Hodgson said:

I think those countries usually tackle the problem by building avalanche shelters, no doubt at great expense.

 

I thought aiport trips were basically a "panic button" in the control tower at RAF Valley which swtiches on a normally dark colour light, a bit like having a SPADI ?

I imagine that a 4-mile long avalanche shelter would not be a cheap option!

 

Over the years I guess several different variations have existed, or still do exist.

[uax6]

Why would it need to be integrated with any other signalling system? They stand alone and the rule book will enable this to continue indefinitely..

 

Andy G

[ikcdab]

1 hour ago, Michael Hodgson said:

If it's not too heretical an idea to tinker with it, it could be presumably be modernised a little by fitting a signal repeater circuit which reads through all of the semaphore arms, which could in turn operate (approach-lit) colour light distants to give slightly better warning.  This would of course require a power supply - but I expect it already has electric lamps, and there's what I assume to be a hydro-electric power station in the valley anyway.  Whether the benefit would be cost-justified is perhaps another matter.

I think on the YouTube video the engineer said there was no power. I'm not sure about the signal lamps....

[uax6]

Guess the lamps are the Dorman LED ones that have batteries.

 

Andy G

[iands]

51 minutes ago, uax6 said:

Why would it need to be integrated with any other signalling system? They stand alone and the rule book will enable this to continue indefinitely..

 

Andy G

I was imagining/summising what would be required if ERTMS Level 3 (no lineside signals) was ever implemented on the route - the "wire detection alarm" would need to be interfaced somewhere/somehow, but I guess that might not be a priority at this time. 

[uax6]

But would it? As long as there are cab windows, surely even if there were no other signals, why would you need to replace these? They are on a single track, so the only other train that could be in section would be following in the same direction, so, as I guess the ERTMS is clever enough to keep trains apart if one stops, there will be no problems will there? 
Is no different to the driver finding a boulder on the track anyway.

I just can't see why they need to be integrated, they will probably be the last signals on the network.... and they really could do with giving them a coat of paint!

 

Andy G 

[iands]

Yep, fair point Andy. Just me overthinking a non-existing problem - as usual. 

[Michael Hodgson]

1 hour ago, uax6 said:

Guess the lamps are the Dorman LED ones that have batteries.

 

Andy G

So they've still got a lampman who has to go and change the batteries?

I think I'd rather have the beneift of such heat as there is from oil lamps if I had to go tramping about there in a Highland winter! 

I suppose they don't meed changing every week though. 

 

1 hour ago, uax6 said:

 

I just can't see why they need to be integrated, they will probably be the last signals on the network.... and they really could do with giving them a coat of paint!

 

Andy G 

Rather like the anomaly of the last signal boxes when it's all ROCs might well be the ones that control swing bridges.

Long live the oddball mechanicals !

[Wheatley]

2 hours ago, Michael Hodgson said:

They would probably be triggered by animals !

In my limited experience of 'broken beam' detectors (subsidence detectors at Kirkby Thore on the S&C, designed to protect the railway if the gypsum mine tunnels gave way), they were far better at detecting rabbits and long grass than railway hazards. 

[uax6]

I've no idea if they still climb the signals to change the lamps, but as Dorman do a LED signal lamp it seems a sensible move (There is no oil light signals on NR now, well thats what we are told!). 

 

At 2:17 in the video, you can see a rubber covered wire running down the post from the lamp housing and at 2:56 you can see a loc  in the bushes, so perhaps the batteries are mounted in there?

 

Andy G

[icn]

On 08/03/2022 at 19:10, uax6 said:

But would it? As long as there are cab windows, surely even if there were no other signals, why would you need to replace these? They are on a single track, so the only other train that could be in section would be following in the same direction, so, as I guess the ERTMS is clever enough to keep trains apart if one stops, there will be no problems will there? 
Is no different to the driver finding a boulder on the track anyway.

I just can't see why they need to be integrated, they will probably be the last signals on the network.... and they really could do with giving them a coat of paint!

 

I think there's one significant argument against this: the topic of workload and situation awareness. Drivers will (on such routes) be used to scanning the tracks for dangers and only the cab for signalling - so there's a strong argument to be made that ALL signalling data must indeed be made available in the cab for consistency reasons. I can easily imagine that this topic will necessarily be discussed during an ETCS conversion, although I don't know what "case law" on this matter states - there are indeed good arguments both ways.

 

(In Switzerland, the NBS was actually operating ETCS in parallel with conventional signalling during the transition period. The conventional signals would show green during ECTS operation, but drivers were instructed to follow the conventional signals if they showed a more restrictive aspect. That's not entirely comparable because the entire route had conventional signalling the whole way - at least until they were happy enough with ECTS operation to be able to get rid of the conventional signals. Whereas the WHL would be all ECTS except for a short stretch where external signals are also valid.)

 

All that said - I can't see why ETCS integration would be that hard. You'd need some switches in place of the current signals, so that rockfall status can be fed into the signalling system. Now that the data is available, movement authority can be rescinded at any point in time during the journey as long as there's radio contact (without radio contact however the train can continue as far as it has previously been authorised to move - so I imagine they'd ensure there's radio coverage for the affected section). Or perhaps they wouldn't rescind movement authority, but rather enforce a switch into on-sight driving mode for the affected section.

[5BarVT]

Some good points there icn, although I have a suspicion that ETCS is a long long way from implementation on the west highland line.

 

Regarding integration (or lack of) between line side signals and ETCS you only need to read the RAIB report on the (very) near miss at Llanbadarn Fawr to see what can go wrong.  (OK circumstances were a bit different there, but the principle still stands.)

 

Paul.

Edited March 12, 2022 by 5BarVT
Spelling

[5BarVT]

On 08/03/2022 at 12:47, 5BarVT said:

Looks like I might be wrong about responsibility for them too!

At a dinner in Glasgow tonight and spoke to a man who knows: they were my asset (signalling) back in the 90s.

 

On 08/03/2022 at 17:01, ikcdab said:

I think on the YouTube video the engineer said there was no power. I'm not sure about the signal lamps....

Same man confirmed that the lamps are electrically lit.

Paul.