Kyle of Lochalsh signalling

Julian Roberts
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Kyle of Lochalsh signalling

Postby Julian Roberts » Wed Jul 28, 2021 5:01 pm

Having nearly completed the pointwork for my Kyle locoshed project I'll be soon at the baseboard building stage. However dimensions are not fully decided, the signalling control system needing to be thought out still.

Here is the layout plan/map with provisional baseboards and fiddleyards. The scenic area will be to the left of (Up from) the road bridge which will be the convenient scenic break.
Kyle Templot screenshot.png

To enhance operational and visual interest I intend to include the visible original HR signals within the modelled area that were in situ in 1949, just before BR resignalled the whole terminus.
BR 57955 and 54463 27 June 1949.jpg
Gantry of four high up on embankment (48 50 25 22)

image.png
Showing group of 3 (51 26 36) and locoshed (45 46) signals


So on the signal diagram below (which is the other way round to my layout diagram, sorry) that is the gantry of four (48 50 25 22), the two shunt signals from the yard (45 46), and the group of three (51 26 36). The locations of these signals are marked S.P. on the map/diagram. Photos show that 25 was not a shunt signal, but like 50 a normal semaphore.

Kyle Signal diagram.png


Could I ask knowledgeable folks here what operations are likely implied by the gantry of four (which BR eliminated)? The implication would seem to be (to me as a layman) that locos/trains will do interesting things (stop, reverse, shunt...) in the short distance between this gantry and the group of three at the start of the single line, and if so this is what I'd like to happen on the layout.

The Up and Down lines are both reversible, Mark Tatlow informs me. I also note his comment on his blog that the HR tended to oversignal. The BR scheme considerably slimmed down this one AFAIK.

I expect there were a whole load of local conditions/regulations which I will attempt to ascertain from the HR Society in addition to general principles.

I wonder for example whether it was possible for a loco/short train to be held stationary at danger occupying one or both of these lines, and for a loco to be signalled in or out of the shed. I also wonder in what circumstances a Down train (towards the station) might be signalled past 51/26 yet held at the gantry of four.

Acknowledging here Dave B having given much help already, many thanks Dave.

JFS
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Re: Kyle of Lochalsh signalling

Postby JFS » Thu Jul 29, 2021 8:04 am

Hello Julian,

My goodness, they must have had a lot of money to burn - I have never seen a more over-signalled layout!! I struggled to read the diagram so I have had a go at wiping some of the muck off it ... I am interested in the number of spare LEVELS ... Spell checker threw a wobbly ...

I don't claim particular expertise, but I don't agree with your interpretation of the gantry. I think it is not actually anything more than a routing signal.
Thus 22,25 apply to backing movements down the Up line and 50, 48 apply to running movements down the Down Line. The locking would be arranged so that either 22 OR 25 would have to be reversed before 26 could be cleared. And 50 OR 48 would have to be reversed before 51 could be cleared. No train or loco could therefore ever be "held" at the gantry.
This would therefore mean that a driver seeing 50 clear would know he had a clear route into the station but which route it was, he would only know when he saw the routing signal - which might well be at the same time. Obviously, if he has already seen 52 clear, he would know that 50 and 51 were both clear.
Despite the extravagent signalling, the layout is very restrictive with direct entry to just a single platform for passenger trains.
Such arrangements were very common before the days of route indicator - Brighton was prehaps the most complicated example: in LBSC days, anything up to 4 routing signals had to be cleared in order back from the pltforms before the Home signal could be cleared.

Edit:- I should have added a caveat to the above - and that is the fact that the Section signal is co-located on the home signal post - thus trains shunting would be brought to a stand the wrong side of the Homes. However, I think that the home signals would still have to be cleared before such moves could back into the station to indicate that the route was set and locked.

Hope that helps.

Howard

Kyle SBD-1.jpg

John Palmer
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Re: Kyle of Lochalsh signalling

Postby John Palmer » Thu Jul 29, 2021 10:37 am

I assume that the 'bow ties' are the Highland version of a shunt signal rather than a wrong road signal (with which use I am more familiar from S&D/LSW practice).

I note from Julian's Transport Library image that 25 was changed from a shunt signal to a running signal, (though possibly one with a short arm). This leads me to wonder whether the layout did, in fact, permit a direct run into both up and down platforms for passenger trains. It's clear that 14 needs to bolt the facing connection 42 for departing passenger trains, but the fact that 14 is adjacent to 13 in the frame makes me wonder whether this FPL simultaneously bolts both 13 and 42 points, in which case all the necessary FPL's are in place for direct admission of a passenger train to the up platform. Similarly, since 31 and 32 are evidently in place to permit a departure from the down side platform, FPL 40 must presumably lock 41 points normal as well as 39.

I wonder how often a shunt movement ever had to pass over 43 points, because for many purposes a routing via the turntable siding will be available, and permits a transfer of stock from one side of the layout to the other. In such a case I can see some value in being able to hold a movement at 22-25-48-50 whilst such a transfer is in progress.

I can't see any purpose for 30 shunt signal that isn't already fulfilled by 31 since both, presumably, can read no further than the gantry carrying 32.

Edited to add that the Baile photograph shows the home signals/section signal are mounted on a bracket immediately adjacent to the toe of 43 points. This means that any shunt making use of that turnout would have to go beyond the bracket (and 44 lockbar) before making a facing movement over the turnout, and moreover would have to pass the section signal. Does that strengthen my case for suggesting that such shunts would have been rare, and that use would have been made of the turntable siding instead?

A certain minimum of road knowledge would be required to run into this station after dark. If you weren't aware of it, you might easily draw up close to the gantry* carrying 51 and 26 and by doing so lock up the approach by standing on 44 lockbar.

(*sorry, I meant bracket)
Last edited by John Palmer on Thu Jul 29, 2021 5:22 pm, edited 1 time in total.

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Noel
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Re: Kyle of Lochalsh signalling

Postby Noel » Thu Jul 29, 2021 4:52 pm

John Palmer wrote:I assume that the 'bow ties' are the Highland version of a shunt signal rather than a wrong road signal (with which use I am more familiar from S&D/LSW practice).


Derek Munday referred to then as arms supplied by Stevens and Co. to permit backing movements, and described the Highland/GER type as a smaller version of the type supplied to the LSWR and others. The large gantry with 4 and 32 mounted on it shows subsidiary signals as discs, suggesting to me that these are the shunting signals, and that the "bow ties" really are backing signals only.

John Palmer wrote:This leads me to wonder whether the layout did, in fact, permit a direct run into both up and down platforms for passenger trains.


I think that the diagram shows that this was the case. There is a bracket carrying 26 and 51 (36 faces the other way), with splitting distants 27 and 52 respectively. It is difficult to put any other interpretation on these except that they are providing for arrival to both sides. 2, 29 and 30 then allow for trains and engines being backed out of the platforms so far as the gantry (and 2 would not be necessary unless there were arrivals this side), 1 allows propelling moves from the wharf to the main (fish vans for collection by a train engine, perhaps?), 23 and 24 control propelling moves through points 11, and 22, 25 and 48 allow propelling moves into West Sidings, Mid Sidings and East Sidings respectively. If so, then the implication is that moves between East and West sides involved using the main line outside the advanced starter. I doubt that the turntable road was used; it's rather short for the purpose, and would mean trespassing on the loco department's territory.
Regards
Noel

Julian Roberts
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Re: Kyle of Lochalsh signalling

Postby Julian Roberts » Thu Jul 29, 2021 8:43 pm

Hello Howard, John and Noel

I'm really grateful for your considerations, and thank you for clarifying the diagram Howard. I should have acknowledged that this is from Peter Tatlow's book on the line.

There are lots of things here I will need to take time to digest. One issue is whether Down trains could arrive on the Up side, and vice versa. Mark Tatlow said in previous correspondence that the lines are reversible. There is another photo in his father's book showing an Up passenger train waiting to depart from the Down side pending the arrival of a Down passenger train.

Here are two photos of shunt moves. One is using the turntable road as a headshunt. This was one of the appealing factors of the location to me, that a shunt between the Down and Up side of the station involved coming right up here if there was not to be a blocking back into the Section. Thus a locoshed layout involves quite a lot more than loco movements.
Shunt move.PNG
Shunt from turntable road
Shunt move.PNG (204.79 KiB) Viewed 1791 times

On the other hand trains were infrequent and perhaps blocking back was no big deal. This photo shows a shunt reversing back on the Up line, with the signal 25 cleared. But I must confess my knowledge is hazy - is it right that shunting beyond 36 involved "blocking back", i.e.communication with the next signal box etc?
Screenshot_2020-05-24-19-54-52.png
Shunt on Up line

I'm not modelling beyond the gantry of four so exactly what the other signals towards the platforms did isn't of practical concern, other than for my (hopefully) eventual general understanding.

There is 1200mm between the gantry (the red target mark) and the blade tips of 43.

Kyle layout detail.png


I think my main question arising is if I was doing the shunt move in the second photo. Let's say it is moving the train from the West Sidings to the Up platform. When pulling out of the West Sidings let's say it didn't need to move beyond 36 so that remains at danger. So then it is moving back to the platform - 25 is cleared, but would 26 have to be cleared too? If I understand you Howard you're saying yes it does.

Subsidiary question - for a shunt move back from the turntable road, say to the East Sidings, 45 would be cleared, but would 48 be cleared too? John I think you imply not, and that another movement could be being held there.

Noel I have to make the admission that I forget the difference between a backing signal and a shunting signal. However I only need as much knowledge as is necessary to operate this layout realistically....At home I have a picture of the gantry with 32 and 4. I think all the signals marked as a circle are arms that look like these bowties.

While you're nearby Howard, my immediate practicality is how much space to allow for a physical interlocking if I go down that route rather than an electrical one. My aim is not for totally prototypical interlocking, but sufficient for a move to be impossible unless correctly signalled, and signal to be possible only with appropriate points set. I reckon I'll need these 9 signals and 3 turnout/crossovers, plus non-modelled 32 and 4 to allow Up movements on both tracks, though unspecific as to where the move is going. I think the Society levers are in groups of 5 so I'd need 3 groups. How much space do they take up with interlocking, or is that like asking how long is a piece of string? I know this doesn't include locks 14 40 and 44 but there are no passengers here...

John Palmer
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Re: Kyle of Lochalsh signalling

Postby John Palmer » Fri Jul 30, 2021 1:07 am

Julian, in answer to the question you particularly directed to me, my surmise is that 45 shunt is released by 41 points reverse, but that 41 reverse must lock all four signals on the bracket (22-25-50-48). It appears that 45 reads not only over 41 points but also 39 points up to 47 and 49.

Regarding your question about a West Sidings to Up Platform shunt that doesn't go beyond the bracket carrying the homes and the section signal, I would expect 25 to be cleared but not 26 – though I fear Howard may disagree with me! Suppose, prior to this shunt, there has been a duly authorised engine movement into the single line section, and that said engine is still standing in rear of home signals 26 and 51. In those circumstances you would not want to clear 26 as well as 25, since clearing 26 is open to interpretation by the driver of the engine standing in section as authority for him to move inside the homes, so bringing him into conflict with the shunt to Up Platform movement you have authorised by clearing 25.

'Is it right that shunting beyond 36 involved "blocking back"'? Not necessarily, as you could simply obtain Strome Ferry's authority to issue a token that would permit the shunting movement to enter the single line section. (This assumes that the section is controlled by returnable token instruments, so that you can restore the token and resume normal working once the shunt is 'back inside'). But Regulation 16 of the LMS regulations dealing with signalling involving the Electric Token Block System provides 3 exceptions to this need to draw a token:

1) where shunting tokens interlocked with with the token instruments are provided;
2) by obtaining authority to foul the single line section from the signalman at the opposite end of it by means of a 'blocking back' bell signal (3-3) that is acknowledged; or
3) by permitting a shunting movement to foul the single line section without first giving the 'blocking back' signal whilst another train is travelling away from the token station where such fouling is to occur, and before 'train out of section' for that train has been received from the token station at the opposite end of the single line section. In such a case, if the single line section remains obstructed by the shunt when 'train out of section' is received, the signalman concerned must immediately give the 'blocking back' signal to the token station at at the opposite end of the affected single line section.

You can see that exception (3) carries a heightened level of hazard because, beyond the extent to which he can see for himself that the section is clear with Mk 1 Eyeball, the signalman availing himself of it has no way of knowing that the train proceeding away from him will be clear of the shunt he has authorised until he receives the 'train out of section' signal for it. It is also anomalous in that the signalman at the opposite end of the section is presented with a fait accompli – the obstruction is there, even though he has not authorised it, as would normally be the case for a 3-3 blocking back exercise.

Sorry, long and tedious technical reply to the questions you raised.

Alan Turner
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Re: Kyle of Lochalsh signalling

Postby Alan Turner » Fri Jul 30, 2021 6:25 am

John Palmer wrote:
You can see that exception (3) carries a heightened level of hazard because, beyond the extent to which he can see for himself that the section is clear with Mk 1 Eyeball, the signalman availing himself of it has no way of knowing that the train proceeding away from him will be clear of the shunt he has authorised until he receives the 'train out of section' signal for it. It is also anomalous in that the signalman at the opposite end of the section is presented with a fait accompli – the obstruction is there, even though he has not authorised it, as would normally be the case for a 3-3 blocking back exercise.


Not peculiar to the LMS, that regulation is enforce now and used now.

It's not a particularly heightened hazard because the shunt needs the authority of the signalman because the departing train prevents the starting signal being lowered. So the shunt is only authorised as far as is necessary for the shunt and as far as the line is clear.

As to the fait accompli yes but all you are saying is don't offer me a train - if you do it will be refused.

regards

Alan

Julian Roberts
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Re: Kyle of Lochalsh signalling

Postby Julian Roberts » Fri Jul 30, 2021 8:54 pm

John thank you very much for that full explanation.

Regarding the contrary opinions on some of the working -

As has been previously said to me, it's unlikely anyone is still alive who actually worked the system, and so no one can say for definite this or that is wrong when I decide how to operate it.

I will check up on that photo I mentioned showing the Up train waiting to depart from the Down platform when next home. To be honest it would suit me very well if Howard you were right and that the system was so restrictive that only one platform could be used for Down trains. Because that would oblige me to shunt each set of arrived coaches to the Up platform before they could form the next Up train to depart, thus increasing the amount of shunting activity in this modelled area of the shed.

For interest (or confusion, but I hope not) here are two photos showing the replacement BR signalling.
Attachments
kyle signal.jpg
Photos 3.PNG
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grovenor-2685
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Re: Kyle of Lochalsh signalling

Postby grovenor-2685 » Fri Jul 30, 2021 10:08 pm

I would say that the existence of splitting distants makes it clear that there is a running route into the up platform, as well as the junction home signal!
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Keith
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Julian Roberts
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Re: Kyle of Lochalsh signalling

Postby Julian Roberts » Tue Aug 31, 2021 8:17 pm

Planning the baseboards still...sorry if this is a naieve question:

I'm wondering how to control the engine shed exit and how many levers will be needed. Looking at the signal diagram, am I right to infer that to exit to the Down line (or enter from it), both 41 and 42 must be reversed?
Attachments
Signal diagram cleaned up by JFS.jpg
Thanks to Howard for cleaning this up
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Re: Kyle of Lochalsh signalling

Postby grovenor-2685 » Tue Aug 31, 2021 8:33 pm

Yes.
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Keith
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Julian Roberts
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Re: Kyle of Lochalsh signalling

Postby Julian Roberts » Wed Sep 01, 2021 6:57 am

Thanks Keith for both your posts here!

Julian Roberts
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Re: Kyle of Lochalsh signalling

Postby Julian Roberts » Sat Oct 09, 2021 11:46 am

Very kindly I have been given a 1963 signal diagram. I think it may be possible to infer from it how the bracket of 4 HR signals that interest me were used - at least sufficiently for me to operate reasonably prototypically unless more definite contrary information came up. So here goes with what I've inferred from the diagram....

20211008_110744.jpg
Title page

20211008_110926.jpg
Overview


The useful information here is that one of the ground signals 8 9 15 16 that replaced the bracket of 4 48 50 25 22 has to be cleared before a movement can be made from both the main line home signals AND the loco yard.
20211008_111145.jpg
Yard and ground signals

Loco yard exit signals 6 and 13 (that replaced HR 45 and 46) have to be preceded by pulling 15 / 16, or 8 / 9.

Home signal 2 indicates a route into either platform and is preceded by either 9 or 15 (HR 50 or 25). Calling on signal 3 accesses all routes and has to be preceded by 8 9 15 or 16.
20211008_111232.jpg
Home signal

There was another BR ground signal 14 to access the middle sidings which I'm assuming was included in the meaning of HR signal 22.

My takeout from this is that I'll go by the same protocols but with the HR signals.**

So anyone with more than my hazy understanding ;) of these things got any corrections to make to my assumptions here?

**Edit In the case of the Home signals, 51 will be preceded by either 48 or 50 and 26 by 25 or 22. From the yard 45 will be preceded by 48 or 50, 46 by 25 or 22.


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