Signalling for modellers who don't know much about signalling

[big jim]

No such thing as ERTMS being actively used in the UK yet, only ETCS, the traffic management software to make it into ERTMS (although only ever in a control centre and not in the cab, a train driver never uses ERTMS) is only just about to be put on trial

Simon

so whats the cambrian then?

 

i understand the components such as etcs and the like making up the system but my training was called the 'ertms course' and as a driver i drive ertms fitted locos

 

confused of crewe!

[Chimer]

>>>It shows the junction, it shows the two stop signals needed to safeguard it, and it shows without any words why they're needed.  To people who just want to get things a bit more right, that's all they need. 

 

That would depend upon what it was that people wanted to get right, and how far they wanted to go towards being correct. For example, the picture as shown IMHO would not stop a modeller committing the faux pas of having trains approaching the signals on both lines at the same time, even if both arms were 'on'. (S)he would need to understand about accepting trains under Regulation 4, not fouling the Clearing Points, possible provision of Outer Homes etc.

 

OK, I need to add to my understanding here, always willing to learn ....... My assumption from the picture (most recently see post #161) was that the van train would have passed a distant at caution, so approached the junction ready to stop, while the express would either have passed its distant at caution and approached similarly ready to stop, or passed it at clear and thundered happily on knowing the stop signal at the junction (and the points) would be in its favour.  I had no idea they couldn't approach at the same time, so yes, I might well commit the suggested faux pas on my model.  My question, then, how would the approaches to the junction be signalled (off scene, obviously, as far as most models would be concerned) to prevent this happening?  In semaphore days please ......

 

P.S. If you could avoid using "in advance", "in rear" and "read to" in any explanation it would be helpful - I know what all these mean in English, but not in Railwayese!  

 

P.P.S.  I'm still not convinced I (or anyone else) needs to know about Reg 4, etc., to simply get those two signals in the right place before (in advance of ? in rear of ?) the junction on a model - but my supplementary question is a genuine one.

 

Thanks

 

Chris

[Junctionmad]

OK, I need to add to my understanding here, always willing to learn ....... My assumption from the picture (most recently see post #161) was that the van train would have passed a distant at caution, so approached the junction ready to stop, while the express would either have passed its distant at caution and approached similarly ready to stop, or passed it at clear and thundered happily on knowing the stop signal at the junction (and the points) would be in its favour. I had no idea they couldn't approach at the same time, so yes, I might well commit the suggested faux pas on my model. My question, then, how would the approaches to the junction be signalled (off scene, obviously, as far as most models would be concerned) to prevent this happening? In semaphore days please ......

 

P.S. If you could avoid using "in advance", "in rear" and "read to" in any explanation it would be helpful - I know what all these mean in English, but not in Railwayese!

 

P.P.S. I'm still not convinced I (or anyone else) needs to know about Reg 4, etc., to simply get those two signals in the right place before (in advance of ? in rear of ?) the junction on a model - but my supplementary question is a genuine one.

 

Thanks

 

Chris

Under normal acceptance criteria, the express could not be accepted until the branch freight had been brought to complete halt at the relevant junction signal , hence the incorrect idea that both trains can proceed towards the junction to be then halted at the stop signal.

 

Hence the reference to unprototypical behaviour etc on model railways. The correct approach , in the absence of a modelled block section., would be to delay the branch train at the stop signal before the express appears to travel through the junction. I.e. The trains appear sequentially at the junction but never simultaneously

 

Ps I never understand the confusion over " advance " or " rear " in the context of railways.

 

Simply imagine a train travelling in the normal direction on the line , in advance , is in the direction of the train travel , in the rear is in the opposite direction

Edited September 7, 2017 by Junctionmad

[Reorte]

A quick Google found a picture of the same junction with an HST through the mainline and another train waiting on the branch, always find it interesting to see essentially the same scene but at a different time. It was colour lights by then so a bit less informative since they faced the opposite way to the picture.

 

Interesting points about the branch train having to be at a halt - it sounds similar to the points earlier in the thread about shunting in the station example?

[meil]

_{I believe this topic has drifted (so what's new!). What I thought the original OP actually wanted was guidance on where signals were sited and what sort of signals were used and where.}

 

_{The topic has moved on to how those signals were used. That is a different issue but unfortunately we have a stand being made by some effectively saying "if you don't know how to operate them according to the rules we wont help you select the appropriate signal and tell you where to site it". I don't think that is helpful as really they are two different matters. Just because someone does not know how to correctly operate the signals doesn't mean they can't be put in the correct place.}

 

_{Of course what type of signals and where they are placed depends on Company, date and operational requirements - and that is an interesting journey in itself. So I agree you can't answer the simple question "how do I signal this layout" without a lot more information - but not knowing how to operate the signals when installed in not a bar to placing the signals.}

[Chimer]

Under normal acceptance criteria, the express could not be accepted until the branch freight had been brought to complete halt at the relevant junction signal , hence the incorrect idea that both trains can proceed towards the junction to be then halted at the stop signal.

 

Hence the reference to unprototypical behaviour etc on model railways. The correct approach , in the absence of a modelled block section., would be to delay the branch train at the stop signal before the express appears to travel through the junction. I.e. The trains appear sequentially at the junction but never simultaneously

 

Ps I never understand the confusion over " advance " or " rear " in the context of railways.

 

Simply imagine a train travelling in the normal direction on the line , in advance , is in the direction of the train travel , in the rear is in the opposite direction

 

OK thanks but:

 

para 1 - if the express cannot be accepted, where is it held and by what?  And has it passed the relevant distant (obviously at caution) before it is held?

 

para 2 - yes, got that, and with a one-man operated trainset (!) its much safer that way anyway.

 

para 3 - so the signal protecting the junction, which comes before the junction, is in rear of the junction despite being in front of it when seen from the cab of the approaching train? And you can't understand why I'm confused?

 

Thanks again in advance for an answer to the para 1 question.

 

Chris

[beast66606]

OK thanks but:

 

para 1 - if the express cannot be accepted, where is it held and by what?  And has it passed the relevant distant (obviously at caution) before it is held?

 

para 2 - yes, got that, and with a one-man operated trainset (!) its much safer that way anyway.

 

para 3 - so the signal protecting the junction, which comes before the junction, is in rear of the junction despite being in front of it when seen from the cab of the approaching train? And you can't understand why I'm confused?

 

Thanks again in advance for an answer to the para 1 question.

 

Chris

 

We are wandering a bit into a mini tutorial.

 

1 - no, it would be held at the previous box (unless there is an outer home but I've kept it simple)

3 - in rear is relative to a fixed position, not from a random viewpoint, otherwise every term would be useless - "in front of" is only in front until you pass it.

Imagine you are standing at the signal and looking in the direction a train would travel - in rear is behind you and in advance is in front of you - simples.

[Ray H]

I understood that the OP was attempting to explain some basic signalling elements to fellow modellers in a reasonably easy to read "thread".

 

Unfortunately his initial post contained some inaccuracies and although intended to incorporate a jargon buster then used words not described in said jargon buster.

 

I have followed this thread from the start and appreciate its intention. However there is no one size fits all explanation that will in a simplistic way achieve what the OP was attempting to do without some form of explanation about the system used for correct implementation.

 

It is simple things like trying to educate the reader to understand/use the correct definitions of signals - it is surprising how many people use the words home signal when they're actually referring to a stop signal that performs a different roll. There was one thread on here a little while ago where the writer's explanation of block sections was completely wrong.

 

It is fairly unlikely that a basic explanation could be presented in a totally correct and unambiguous manner without a lot of effort from a number of people. Any discussions between those posting the explanations would need to take place away from the thread concerned to avoid confusing readers and the thread would need to only feature ratified posts if readers seeking the relevant knowledge were not to drift away because they're unable to sort the wheat from the chaff.

 

There is also the risk that a reader may follow the thread until they come to an explanation that they believe describes their layout's requirements when in fact a subsequent post details certain exceptions into which the reader's layout falls.

 

The suggestion was made at a fairly early stage in this thread that those wanting to signal their layout appropriately should post details of their layout and seek guidance for their own situation. Doing so highlights the problems that a definitive thread would demonstrate because appropriate signalling doesn't just require a track diagram on its own. It needs numerous supplementary information and it is the requirement to understand this supplementary information (and the number of possible variations on a theme) that should demonstrate that a one size fits all answer is seldom possible (if at all).

Edited September 7, 2017 by Ray H

[phil-b259]

 

para 3 - so the signal protecting the junction, which comes before the junction, is in rear of the junction despite being in front of it when seen from the cab of the approaching train? And you can't understand why I'm confused?

 

 

It all comes down to what you are using as a reference point - and as in real life that reference point changes depending on where you are looking from.

 

For example if you live in London then both Birmingham and Manchester are "Up North". If you live in Birmingham then London is "Down South" but Manchester is still "Up North"

 

If you translate that into signal posts that person in London could be said to be 'In Rear' of Birmingham and Manchester (i.e. not reached them yet) while a person in Birmingham is 'In Rear of' Manchester, yet 'In Advance of' London.

 

Alternatively at 11:00 in the morning you could say that you are in advance of 'Breakfast' but in rear of 'Lunch'

 

Plenty of other examples can be quoted with no need to involve railway signalling.

 

The key issue is that being 'In rear' of something means that whatever you are describing has not yet arrived at your chosen reference point. Conversely something being 'In Advance of' means it has gone past your chose reference point. However if you then move your reference point then obviously that changes the position of the item you are describing and may mean that what was previously described as 'In advance of' then becomes 'In rear of' the new reference point even if the item itself hasn't actually changed position.

[Talltim]

It's easy to see where the advance/rear confusion comes from. A signal has a front and a back. Rear is a synonym of back or behind yet in signalling terms in rear means in front of. Similarly in advance means behind in signalling terms yet in advance normally means in front of, e.g. A light engine was run in advance (before, in front) of the royal train.

Edited September 7, 2017 by Talltim

[RailWest]

..... A signal has a front and a back. Rear is a synonym of back or behind yet in signalling terms in rear means in front of. .....

Ah, but.....a signal faces the oncoming traffic to which it is intended to apply. Therefore the 'front' and 'back' of a signal are viewed from the opposite perspective than that of the driver of the appoaching train. So there is no inconsistency in terminology really 

[Talltim]

Ah, but.....a signal faces the oncoming traffic to which it is intended to apply. Therefore the 'front' and 'back' of a signal are viewed from the opposite perspective than that of the driver of the appoaching train. So there is no inconsistency in terminology really

Nope, that's confused me!

Take a colour light signal. The light is on the front and it is still on the front wherever you view it from.

I do understand the reasoning behind the signalling meaning of the words, but I do also see the reasoning behind the reverse and so can understand the confusion it causes, that the point I was making.

[ejstubbs]

I find the explanations on the signalbox.org web site useful.  I also found browsing Bob Essery's Railway Signalling and Track Plans informative - he does provide examples of signalling a number of different track layouts, as well as explaining operational considerations.  Heck, I even found some illuminating information in good old Cyril Freezer's Model Railway Signalling.

 

But when it comes to specific situations that don't obviously fit neatly within the basic rules then asking the question here has provided some extremely helpful guidance - as has browsing other modeller's questions of a similar nature, even if their specific layout isn't necessarily identical to mine.  I think that, when asking question of this nature, it really helps to provide a clear track plan and an explanation of what the intended traffic is supposed to be (eg which lines disappearing off scene are main lines or branch lines, which types of goods are intended to be handled in which sidings and so forth).  Annotating the points, platforms, sidings/goods facilities and (if you already have an idea of what might work) signals on the diagram make it much easier for people to then explain where amendments to layout, operation or signalling might be required.

 

While I respect what the OP was setting out to achieve, I personally doubt whether a forum thread - or, at any rate, a single forum thread - is an effective way to go about it.  (And I do wonder whether some folks expect to get rather too much for free on t'internet when they might be well advised to, you know, buy a book about it, at least to give themselves a grounding...)

Edited September 7, 2017 by ejstubbs

[Compound2632]

I think that, when asking question of this nature, it really helps to provide a clear track plan and an explanation of what the intended traffic is supposed to be (eg which lines disappearing off scene are main lines or branch lines, which types of goods are intended to be handled in which sidings and so forth).  Annotating the points, platforms, sidings/goods facilities and (if you already have an idea of what might work) signals on the diagram make it much easier for people to then explain where amendments to layout, operation or signalling might be required.

 

I tried doing that but it didn't work - the professionals continued to reminisce amongst themselves...

[Ray H]

I tried doing that but it didn't work - the professionals continued to reminisce amongst themselves...

 

My understanding was that it had been suggested that you present your information in a different way. I may have missed you doing so but can understand why you haven't had the information you were seeking if the requested clarification hasn't been provided.

[The Johnster]

I understood that the OP was attempting to explain some basic signalling elements to fellow modellers in a reasonably easy to read "thread".

 

Unfortunately his initial post contained some inaccuracies and although intended to incorporate a jargon buster then used words not described in said jargon buster.

 

I have followed this thread from the start and appreciate its intention. However there is no one size fits all explanation that will in a simplistic way achieve what the OP was attempting to do without some form of explanation about the system used for correct implementation.

 

It is simple things like trying to educate the reader to understand/use the correct definitions of signals - it is surprising how many people use the words home signal when they're actually referring to a stop signal that performs a different roll. There was one thread on here a little while ago where the writer's explanation of block sections was completely wrong.

 

It is fairly unlikely that a basic explanation could be presented in a totally correct and unambiguous manner without a lot of effort from a number of people. Any discussions between those posting the explanations would need to take place away from the thread concerned to avoid confusing readers and the thread would need to only feature ratified posts if readers seeking the relevant knowledge were not to drift away because they're unable to sort the wheat from the chaff.

 

There is also the risk that a reader may follow the thread until they come to an explanation that they believe describes their layout's requirements when in fact a subsequent post details certain exceptions into which the reader's layout falls.

 

The suggestion was made at a fairly early stage in this thread that those wanting to signal their layout appropriately should post details of their layout and seek guidance for their own situation. Doing so highlights the problems that a definitive thread would demonstrate because appropriate signalling doesn't just require a track diagram on its own. It needs numerous supplementary information and it is the requirement to understand this supplementary information (and the number of possible variations on a theme) that should demonstrate that a one size fits all answer is seldom possible (if at all).

 

 

I agree with your criticism of my original posts, Ray.  It was a much harder thing to do in a way that a novice could understand than I'd realised!  Hopefully I have at least set off a discussion that will provide some guidance to those who are need of it, and it won't have been a complete waste of time!

Edited September 7, 2017 by The Johnster

[PaulRhB]

Certainly not a waste of time

 

As I posted before the signal terms have changed because of the confusion within the industry!

Old and new terms below.

Advance = Beyond

In Rear = On the Approach to.

[TheSignalEngineer]

Many railway customs came from the military. If you go forward you advance. If you retreat you move to the rear.

[PaulRhB]

And quite often we wish we had other military assets to deal with certain people

[TheSignalEngineer]

And quite often we wish we had other military assets to deal with certain people

When asked to do a particularly awkward task at work and succeeding my boss said I looked as if I was bomb proof. I replied that I wasn't but there were so many old holes the shrapnel went straight through now.

[St. Simon]

so whats the cambrian then?

 

i understand the components such as etcs and the like making up the system but my training was called the 'ertms course' and as a driver i drive ertms fitted locos

 

confused of crewe!

 

The Cambrian is ETCS Level 2, it's not full ERTMS, the locos are ETCS fitted not ERTMS fitted, in fact they never will be fitted with ERTMS.

 

It's a common mistake that even signalling engineers in the IRSE magazine get wrong, they just refer to anything that runs ETCS as being ERTMS even though you need the traffic management software (soon to be trailed on Western) installed in the control centre to make a line one run by ERTMS.

 

Simon

[Chimer]

Certainly not a waste of time

 

As I posted before the signal terms have changed because of the confusion within the industry!

Old and new terms below.

Advance = Beyond

In Rear = On the Approach to.

 

Hooray!  But when will we see these terms used in the learned discussions on here, I wonder?  Anyway at least I now know my instinctive understanding of the meaning of in advance and in rear will be wrong in a signalling context - unless of course they're being used by someone else who thinks logically rather than in accordance with railway regulations.  And that photograph still shows you where to plant the signals that directly protect a junction .....

 

Ain't it amazing what a throwaway remark can provoke?

[The Stationmaster]

It's easy to see where the advance/rear confusion comes from. A signal has a front and a back. Rear is a synonym of back or behind yet in signalling terms in rear means in front of. Similarly in advance means behind in signalling terms yet in advance normally means in front of, e.g. A light engine was run in advance (before, in front) of the royal train.

 

Simples - just imagine you are standing on a railway line looking in the direction in which trains normally run.  Everything you see is in advance of you, that which is behind you is in rear of you (and you even have something you could tap to remind you where (your) rear is.  On a double line railway where one line is used in each direction then obviously as trains head in those different directions you again simply imagine yourself looking in the direction of travel on that particular line - always 'in advance' is, literally, in the direction in which you are looking and in rear is - as ever - behind you, just like your own rear.  

 

Regrettably the term 'beyond' is anmbiguous as in normal English usage it relates to the direction in which you are looking and not necessarily the direction in which trains are travelling.  Thus when it first appeared in the Rule Book there was a reference to a train standing 'beyond the Home Signal'.  Beyond the Home Signal then depends entirely on where you are standing when you look at the Home Signal.  In rear of the Home Signal (or anything else) is absolutely explicit irrespective of where you happen to be standing.  And that is one reason why it and in advance were used and there's at least one death (of a Shunter) on record where somebody used the term 'in front' instead of in advance.

 

I therefore, for very good safety and risk based reasons, absolutely refuse to use the ambiguous term 'beyond' in any Rule Book which I write (while 'on the approach to' uses 4 words where two will do - look again for simplicity).  The key with terms such as 'in rear' and 'in advance' is explanation and training, and I don't tak about 'Far away Signals' when I mean 'Distant Signals' which was another proposal from the Plain English mob to change the wording in the Rule Book.

 

 

_{I believe this topic has drifted (so what's new!). What I thought the original OP actually wanted was guidance on where signals were sited and what sort of signals were used and where.}

 

_{The topic has moved on to how those signals were used. That is a different issue but unfortunately we have a stand being made by some effectively saying "if you don't know how to operate them according to the rules we wont help you select the appropriate signal and tell you where to site it". I don't think that is helpful as really they are two different matters. Just because someone does not know how to correctly operate the signals doesn't mean they can't be put in the correct place.}

 

_{Of course what type of signals and where they are placed depends on Company, date and operational requirements - and that is an interesting journey in itself. So I agree you can't answer the simple question "how do I signal this layout" without a lot more information - but not knowing how to operate the signals when installed in not a bar to placing the signals.}

 

 

Bit of mixture alas.  And if you want to fully understand it you do need to have a basic grasp of two key areas with semaphore stop signals because they potentially serve two or more different functions.  The basic function of a stop signal is to protect something - that something then falls into several categories -

1. It protects Station Limits (the Home Signal),

2. It protects the entrance to a Block Section (the Section Signal),

3. It protects connections trailing in from other lines and sidings,

4. It protects (and provides route indication) at facing points, & 

5. It protects various other things which can obstruct or impeded the passage of a train such as a worked (by Signalman or Gatekeeper) level crossing or a movable bridge.

6. It can also protect additional signal sections which are provided to assist smooth working of the required traffic levels and train service - that might be involved with block working or it might be to provide capacity for more than one train on the same line within Station Limits.

 

That's the basics - but different Companies and BR Regions did things their own way with that overall situation

N.B. A signal section is the section of line between two successive stop signals

[Compound2632]

My understanding was that it had been suggested that you present your information in a different way. I may have missed you doing so but can understand why you haven't had the information you were seeking if the requested clarification hasn't been provided.

 

One poster did suggest such a thing; I replied highlighting that part of the point of my post had been to take into account the space constraints many encounter, which compromise the realism of the layout in the first place. I thought of producing diagrams comparing the model track plan and signalling with the (fictional) prototype, illustrating the compromises I'd made, but was unconvinced that would help pull the thread in a more 'average model railway'-friendly direction.

[big jim]

slightly off topic sorry!

 

The Cambrian is ETCS Level 2, it's not full ERTMS, the locos are ETCS fitted not ERTMS fitted, in fact they never will be fitted with ERTMS.

 

It's a common mistake that even signalling engineers in the IRSE magazine get wrong, they just refer to anything that runs ETCS as being ERTMS even though you need the traffic management software (soon to be trailed on Western) installed in the control centre to make a line one run by ERTMS.

 

Simon

 

very well explained simon, reading the first sentence jogged my memory to the differences, iirc "full" ERTMS is when the trains can automatically be kept appropriate distances apart via the in train equipment and control centre gubbins working together