Clearing subsidiary signals.

[The Stationmaster]

Thankyou all for your responses. I am slightly better educated.

 

Micknich, Thanks for the images. Para 2 on p 323 seems an odd way of putting the point though.

 

Para three on p323 presumably means any running shunts ahead must be interlocked with a subsidiary under a running signal with route indicator.

 

 

Regards

It's written like that to completely distinguish between the two sets of circumstances, i.e

1. Sub 'off' illuminated with no indication of route and it is effectively exactly the same as a shunting signal - the the route is set only as far as the next shunting signal in advance but be prepared to find it occupied and be ready to stop short of any obstruction.

2. Sub 'off' with an indication of route is in effect exactly the same as a Calling On subsidiary 'off' - i.e. the route is set as it would be with teh running signal/main aspect 'off' but it is occupied by something which the Driver should be prepared to stop short of (with examples described).

 

These two methods basically became standard multiple aspect signalling practice and the distinction remained the same although terms used changed a bit and at one stage when working in the second mode the position light also included an illuminated letter 'C' (for Calling On) at bottom left.  But many earlier signal were never altered to that and it seems to have only gone in in some new new work between the late 1950s and approx 1963 - those signals which gained it subsequently lost the 'C' during the mid 1960s when everything was gradually brought into line with what is described in the notice posted by Micknich.  It was also made clear in the Rule Book that passenger trains were not permitted to pass a signal with a sub unless an indication of route was shown.

[micknich2003]

Talking of NERailway, why does it have miniature semaphore signals ( including on brackets) to control backwards shunting moves? See on John Hinson's excellent site Pontop and Aclington)

 

 I have asked my very learned friend Richard, he sent me the attached 1910 page from the NERly, and what we would now call "Signalling Principles".

[ColHut]

Thankyou Stationmaster. You write :  "It was also made clear in the Rule Book that passenger trains were not permitted to pass a signal with a sub unless an indication of route was shown."

 

When did this rule come into effect?, did it only apply to colour light signals?

 

Micknich: thanks for that. The miniature signals must have cost a fortune. The practice must have been well entrenched in 1910.

 

Regards

[ColHut]

Just one other thing. I had assumed that ground signals reading to crossovers did not prevent a train backing along the line in the normal direction of the points. But this is an error, regardless of direction unless they are yellow arms and it does not apply to the direction of movement.

 

So disc 14 on this diagram at John Hinson' site cannot be passed (except under the shunter's direction) back Up the main, and if cleared probably permits trains to back onto the down main or colliery road ( not sure which) when cleared.

 

http://www.signalbox.org/diagrams.php?id=694

[The Stationmaster]

Thankyou Stationmaster. You write :  "It was also made clear in the Rule Book that passenger trains were not permitted to pass a signal with a sub unless an indication of route was shown."

 

When did this rule come into effect?, did it only apply to colour light signals?

 

Regards

It was implicit in changes made to various Rules in 1938 but it became wholly explicit in an amendment to the Rule Book made in May 1964.

 

The difference between colour light and semaphore signals was effectively self-differentiating because sempahore subsidiary signals functioned as either Calling On, Shunt Ahead, or warning Signals.

 

However the 1964 amendment effectively altered the situation with semaphore subsidiaries which didn't show the 'C', 'S', or 'W' and which had been previously used to serve the dual role of both a shunting signal and a subsidiary (effectively as a Calling On signal.  Hence a number of such subsidiaries - which mainly existed on former LMS lines as far as I have been able to trace in the past - gained electric stencil indicators.  however the whole business of what had become termed as Draw Ahead signals changed several times in the Rule Book - almost certainly to suit the way certain Regions had carried on past Company practice.

Just one other thing. I had assumed that ground signals reading to crossovers did not prevent a train backing along the line in the normal direction of the points. But this is an error, regardless of direction unless they are yellow arms and it does not apply to the direction of movement.

 

So disc 14 on this diagram at John Hinson' site cannot be passed (except under the shunter's direction) back Up the main, and if cleared probably permits trains to back onto the down main or colliery road ( not sure which) when cleared.

 

http://www.signalbox.org/diagrams.php?id=694

 

There were variations in Company practice but generally shunting signals were not used to permit a wrong direction move into a block section (something which has changed as 'Limit of Shunt' boards became far more widespread.   Thus 14 would most likely only be released by 10 standing reverse.  * & 9 are interesting as there appear to be two levers working the same signal - one for each of the two routes from that signal (thus one of them requires 10 reverse, and possibly 11, while the other also requires 12 reverse).  

 

A yellow arm would not be used in a situation like that as it would effectively give the Driver authority to enter the section in the wrong direction.

[ColHut]

Stationmaster, Thankyou very much. I realise I meant the disc operated by 8 or 9, no idea why I wrote 14. But your response has provided me with far more education, so that is a bonus! Perhaps my question makes better sense now. Point taken about yellow arms, I assumed they were for normal direction moves.

 

Can you give me a hint as to which rule changes in 1938 implied that Passenger trains were not permitted To pass a signal with a sub unless a route indication was provided? I have the LNER 1933 rules with amendments up to 1945. Or was this only with reference to colour lights. Sorry if I am not getting this.

 

Regards and thanks again for your patience.

[The Stationmaster]

Stationmaster, Thankyou very much. I realise I meant the disc operated by 8 or 9, no idea why I wrote 14. But your response has provided me with far more education, so that is a bonus! Perhaps my question makes better sense now. Point taken about yellow arms, I assumed they were for normal direction moves.

 

Can you give me a hint as to which rule changes in 1938 implied that Passenger trains were not permitted To pass a signal with a sub unless a route indication was provided? I have the LNER 1933 rules with amendments up to 1945. Or was this only with reference to colour lights. Sorry if I am not getting this.

 

Regards and thanks again for your patience.

It refers to calling on in one Rule and shunting in another (in relation to Draw Ahead signals) - Rules 44 & 47 as amended (I only have the GWR amendments and regrettably not those for the LNER book). As I said it is implicit and not explicit but was always explained to me on the Western by certain Signalling Inspectors that they couldn't see much point in the 1960s amendment as it added nothing to what they already knew (our Chief DI in Cardiff was however a long way ahead of just about everyone I ever knew when it came to Rules & Regs, when he passed you out for a job you knew, after 5 hours with him, that you were never going to be found lacking on that sort of knowledge).

[micknich2003]

https://www.youtube.com/watch?v=eGy9hveGdR4

 

 Have a look at the above 1920's film of Newcastle, it shows numerous ex NERly Calling On arms.

[ColHut]

Apologies for resurrecting this thread.

 

Can someone point me to where is is written, whether principal or regulation, that stop signals only to be lowered if all intervening running shunt signals are clear? Is it in a signalling principles work of some kind, or did I miss it in the regulations or general appendix? Late 1930s LNER.

 

It confuses me enough that fixed signals are defined as stop, distant and subsidiary (rule34), and that some subsidiary signals allow movement to the next stop signal, some only for a particular purpose, like shunt ahead, and others only until the next signal (draw ahead and shunt signals (rule47) LNERl rules 1945.

 

I figure never having worked in real railways I am sometimes missing some basic building blocks .

 

Regards

[RailWest]

AFAIK if a shunt signal is a 'running' shunt, then the interlocking will prevent any main signal in rear from being pulled 'off' unless that running shunt is off first. So it was not in any regulation for the signalman, as it was enforced as a matter of course by the interlocking.

[Junctionmad]

AFAIK if a shunt signal is a 'running' shunt, then the interlocking will prevent any main signal in rear from being pulled 'off' unless that running shunt is off first. So it was not in any regulation for the signalman, as it was enforced as a matter of course by the interlocking.

Did I read this to understand that of a main signal Is pulled off , it can only be done of any intervening ground signals are also off ???????. I didn't think this was so. But I could just be dense

[phil-b259]

Did I read this to understand that of a main signal Is pulled off , it can only be done of any intervening ground signals are also off ???????. I didn't think this was so. But I could just be dense

Yes you are correct - and has been said this is enforced by the interlocking of the relevant signal controls.

[St. Simon]

Yes you are correct - and has been said this is enforced by the interlocking of the relevant signal controls.

Now known as a Preset Shunt (well, at least in Reading)

 

Simon

[Junctionmad]

Yes you are correct - and has been said this is enforced by the interlocking of the relevant signal controls.

Obviously this must be with modern MAS , in semaphores ground signals would not be cleared if the main running signal was cleared. The running signal overrode the ground ones

[ColHut]

One. Other sub question, a running shunt controlling a cross over for a backing moment to a parallel line or siding still cannot be passed at danger even if the train backing up is not intending to use the crossover?

 

Regards

[Junctionmad]

A running shunt is a shunt is best described as a shunt signal on a main running line (as opposed to a siding) that requires to be operated to give a proceed indication before certain main running signals can be cleared to a proceed.

 

Imagine you have the following signals and trains pass them in this order

 

(1) Main running Signal & (2) Subsidiary Signal (i.e. a shunt signal) on the same post

(3) Ground Shunt Signal

(4) Main running Signal

 

Lets imagine that signal (1) is showing a proceed indication and signal (3) is at danger. The driver passes signal (1) as he is entitled to do but finds the next signal (3) telling him to stop. This could be confusing as according to signalling principles, signal (1) can only be cleared if ALL the track between signals (1) and (4) is clear of trains and all points are set correctly and as such there is no reason for a train to stop between (1) and (4).

 

To prevent confusion therefore we arrange the signal interlocking such that signal (1) is prevented from showing a proceed indication unless signal (3) is pulled off to a proceed first.

 

If a shunt move is taking place then signal (3) can remain at danger and the subsidiary signal (2) will be used to authorize movements up to it. Naturally signal (1) remains at Danger

 

Normally you would only get signal (1) OR signal (2) showing a proceed at any given time - however as indicated in this thread the NE region favoured the setup where if (1) was showing a proceed so would (2). It should be noted however that this still doesn't change the fundamental principle that if (1) is shown a proceed then (3) must also be showing a proceed.

Hmm, certainly in single line working with semaphores , I don't believe routes cleared with running signals required intervening facing ground signals to be cleared.

 

Ground signals are just a form of subsidiary signal, if the main running signal is cleared the ground ( subsidiary ) signal can be passed or ignored.

[TheSignalEngineer]

Ground signals are just a form of subsidiary signal, if the main running signal is cleared the ground ( subsidiary ) signal can be passed or ignored.

Not what it says in the Rule Book

[Grovenor]

 

Not what it says in the Rule Book

Terminology and rules have changed over time, hence also the practice.

Note that the Hull Paragon document from 1938 in post #21 specifically describes GPLs as "Subsidiary Signals" and also specifically states that they can be ignored by a driver running on a main yellow or green! The implication being that the GPLs did not have to be pre-set in that installation.

 

(Its pretty obvious that a driver running at 100mph on greens will be unlikely to get enough sighting of a GPL to allow him to stop at it, but given that most running shunts would be in low speed areas like terminal approaches the requirement to pre-set was introduced, IIRC during the 60s modernisation plan, at least it seemed to be new to my colleagues at the time, the aim was to avoid drivers getting confused and making unneeded emergency stops).

 

The NER 1910 document in post #27 has another example of terminology that is confusing in current practice, it talks of detectors and seems to include both what we now call the facing point lock and the detector.

 

Regards

[RailWest]

>>>One. Other sub question, a running shunt controlling a cross over for a backing moment to a parallel line or siding still cannot be passed at danger even if the train backing up is not intending to use the crossover?

I'm not sure that I understand that question. If the shunt is controlling a 'backing' movement, then by definition you must be going in the 'wrong' direction, so is unlikely to be a main signal for that movement as well anyway.

On a more general point.....

The practice with shunt signals varied over time and with railway company. At one time, probably initially because of the inability of early designs of interlocking frame to do 'conditional' locking, shunt signals only read for one route over a point, which was usually the 'diverging' route. Consequently as main running signals usually applied to the 'normal' (ie non-diverging)route, then they were not interlocked with any shunt signals at facing points and clearance of the main signal authorised the driver to ignore any subsequent facing shunt (up to the next stop signal) which was at 'on'. Later, with the improvement to locking frame designs, it became more common to make any such intervening shunt signals into 'running' shunts and enable them to apply to both routes, hence the need to pull the shunt off first before the main stop signal could be cleared.

In such a situation then it would be possible - in theory - if a problem occurred after the train had passed the main stop signal 'off', but before it reached the running shunt, for the signalman to put the main signal back to 'on' and then the running shunt back as well. Given the time that it would take to do those operations, the train might well have passed the shunt as well, but if not AND the driver happened to spot that it had gone back, then he should try to obey that signal and stop the train - tho' giving his possible speed and the likelihood that the 'problem' was only a short distance ahead, it might not make much difference. IMHO it would seem unreasonable to expect a driver of a train running at normal line speed under clear signals to observe AND obey every intermediate running shunt.

[ColHut]

>>>One. Other sub question, a running shunt controlling a cross over for a backing moment to a parallel line or siding still cannot be passed at danger even if the train backing up is not intending to use the crossover?

 

I'm not sure that I understand that question. If the shunt is controlling a 'backing' movement, then by definition you must be going in the 'wrong' direction, so is unlikely to be a main signal for that movement as well anyway.

 

To be clear, the particular question above was just a general question about shunting signals.

 

Regards

[Grovenor]

One. Other sub question, a running shunt controlling a cross over for a backing moment to a parallel line or siding still cannot be passed at danger even if the train backing up is not intending to use the crossover?

 

Regards

A shunt signal used to control movement over a trailing crossover or siding connection would not normally be described as a running shunt, and cannot be passed at danger except by signalman's specific instruction. A shunt signal reading in the wrong direction on a running line can only read up to another signal or limit of shunt board, without one or other of these it has to read over a crossover onto the correct direction line or into a siding.

 

At terminals and similar situations a train/loco pulling out of one platform then backing into another may use a shunt signal that becomes a running shunt for trains arriving in those platforms. This is the situation illustrated in the Hull Paragon diagram above.

Regards

[phil-b259]

Obviously this must be with modern MAS , in semaphores ground signals would not be cleared if the main running signal was cleared. The running signal overrode the ground ones

Wrong! It applied in mechanical days too and exists in mechanical signalling on both the national network plus heritage operations.

 

You need to remember a fundamental rule of signalling - If a main running signal (starter, home, stop or whatever you call them) is cleared to a proceed (or off) position it tells the driver that the line between it and the next main signal is clear of trains and he will not need to stop. A standalone shunt signal (as opposed to one co located with a main signal) commands ALL trains (or locos) to STOP when in the danger (or on position), there is - and as far as I know there has never been an exemption that says drivers may disregard any signal in normal operations.

 

The only situation where a main signal overrides a shunt signal is when both such signals are physically co located in the same place and thus a driver will technically see a proceed indication as well as a stop indication. In such a scenario one the proceed does override the stop command but that only is possible because there are two signals. The same principle applies to stacked disc shunt signals by the way.

[beast66606]

Hmm, certainly in single line working with semaphores , I don't believe routes cleared with running signals required intervening facing ground signals to be cleared.

 

Ground signals are just a form of subsidiary signal, if the main running signal is cleared the ground ( subsidiary ) signal can be passed or ignored.

 

On several occasions I've seen a train coming to a grinding halt at Liverpool Lime Street after getting a yellow at the stop signal controlling entry to a platform and finding an in-route GPLS had returned to danger due to a floating track circuit.

 

Runcorn signal 11 -  22 September 1991, taken with permission and collars on the levers, this signal controlled Pendolinos, 66s, 56s, etc. etc and was preceeded by a 4-aspect colour light, with shunt (RN9/RN10)

 

 

lever plate - 16/17 are the connection to the Folly Lane line - 18 is listed erroneously, it was a spare at the time. There was no "released by" number on the plate of RN10, the main aspect preceeding it (I suspect some Dymo tape had fallen off). RN9 - had 16,17 and 11.

 

 

[Junctionmad]

Wrong! It applied in mechanical days too and exists in mechanical signalling on both the national network plus heritage operations.

You need to remember a fundamental rule of signalling - If a main running signal (starter, home, stop or whatever you call them) is cleared to a proceed (or off) position it tells the driver that the line between it and the next main signal is clear of trains and he will not need to stop. A standalone shunt signal (as opposed to one co located with a main signal) commands ALL trains (or locos) to STOP when in the danger (or on position), there is - and as far as I know there has never been an exemption that says drivers may disregard any signal in normal operations. The same principle applies to stacked disc shunt signals by the way.

The only situation where a main signal overrides a shunt signal is when both such signals are physically co located in the same place and thus a driver will technically see a proceed indication as well as a stop indication. In such a scenario one the proceed does override the stop command but that only is possible because there are two signals.

I stand corrected, I had always assumed facing disks only applied to shutting movements within the limit of shunt , what you now say is that ground disks with red bar have exactly the same status as in effect intermediate running signals , that's a new one

[Junctionmad]

I stand corrected, I had always assumed facing disks only applied to shutting movements within the limit of shunt , what you now say is that ground disks with red bar have exactly the same status as in effect intermediate running signals , that's a new one

So therefore it follows that regulation 39 (a) must apply to disks ?