Shunting in electric token block areas

[Junctionmad]

Here's a question , I should know the answer to, but don't

 

With electric token block and obviously on a single line , how are station limits applied , are these still home to starter ? , hence the limits will be different in each direction ?

 

Since each access in each direction requires a token , I presume there is no concept of " blocking back " Rather a token request needs to be issued and the relevant starter pulled off ? Or is it that once the clearance point of the home is fouled even if that , is situated in the rear of the starter , then a block back inside the home would be issued ?

 

Where an advanced starter wasn't present , or shunting took place "in advance " of the starter ( i.e. A yard in advance of the starter ) , would that have always required a token , where shunt ahead was used would this type of signal have applied ?

 

Am I correct , in a generic sense here ? ( leaving aside special regulations or regional oddities etc )

Edited September 10, 2017 by Junctionmad

[RailWest]

Ironically, I had to look this up just recently, but I forget the Regulation number now :-(

 

Don't know whether things have changed in recent years, but.....

 

IIRC:-

 

1. Provided no tokens were out, you could shunt into a section by Blocking Back without needing a token.  This could be done at both ends of the same section at the same time if required.

2. If there was a token out for a train already in the section going away from you, then you could shunt into the section behind it without Blocking Back, but you had to BB immediately if you got Train Out of Section before your shunt had been withdrawn.

3. If there was a token withdrawn at the other end for a train to come towards you - keep out!

[The Stationmaster]

Interesting one,  As far as shunting into the section is concerned Chris has given the answer.  Technically it was (not so sure about the current situation without checking) called 'Occupation of The Single Line For Shunting or Engineering Purpose' and basically it's broadly equivalent to a Block Back in rear of ('outside') the outermost Home Signal.   It doesn't matter if the shunt move starts as an extension of a right direction train movement or if it's a shunt in the wrong direction - the key point is that it will pass outside (the protection of) the Home Signal.

 

Addendum.  At this point it would be more than helpful to clarify what is meant by 'the Home Signal' in this Regulation.  The key point is that the movement will shunt onto the single line and that will mean that even if an additional Home Signal is provided for acceptance purposes, at least 440 yards in rear of the second, or subsequent, Home Signal the procedure applies if the movement will need to go outside that second signal and not the outermost one.  Although it has been arranged rather differently - for reasons explained in another (reply) post - the signalbox diagram below can be used to illustrate this.  In this example Signal 25 is the additional Home Signal but the 3-3 'Occupation of the single Line ... etc' bell signal would need to be sent if the movement will need to pass outside the second signal which in this case is the bracket signal 20/22/24  as can be seen this second signal (20/22/24) is the Home Signal at the end of the single line, or in terms of the shunting movement, the Home Signal at the point where the single line commences.

 

 

There has been no such thing as 'Shunting Into Forward Section' in the Electric Token Regulations for over a century.  So even if a movement enters the section for shunting purposes in what would be the right direction it is still the same procedure IF it will go outside the Home Signal e.g. a train needs to shunt a siding which is in advance of the Section Signal  but that siding is in rear of the Home Signal for the opposite direction.

 

The reasons for doing it like this are relatively straightforward once you think them through.  Station Limits are, as you said, likely to be different in each direction and may well overlap each other because they run - as on Absolute Double Line Block - from the outermost Home Signal to the most advanced Starting Signal (i.e. the Section Signal).  But in many instances the latter will actually be in the block section in the opposite direction over the single line because that finishes at the Home Signal and equally the outermost Home Signal, if two are provided, is actually well within the single line section.  Thus it was usually inevitable that a shunt move would enter the block section which ended at the Home Signal (Home Signals further out to create a Clearing Point were not too common on single lines).  

 

The big advantage of equating the shunt move to a Block Back is that you are not signalling a train or movement forward to the next signalbox thus it is feasible to make a move into a section occupied by a train that is going away (which can be very useful where sections are long).  Plus, as Chris noted, in most cases you can make the shunt without drawing a token (although in some places special shunting tokens were used) and you can make shunts simultaneously at both ends of the section.

 

In some places where shunts took place regularly off the 'right' line a 'Shunt Ahead' subsidiary arm would ideally be provided beneath the relevant stop signal, particularly the case on the GWR.  Still called a  Shunt Ahead arm because what is being made is a shunt movement into the block section although it is block signalled using the 3-3 bell code (which is Blocking Back Outside the Home Signal in double line block).

 

You question about an Advanced Starter is an interesting one and has been the source of some discussion over the years.  Contrary to the view expounded by some people it is not really relevant - the key factor is whether or not the shunt move will go outside (the protection of) the Home Signal/second Home Signal.  Think of it at its simplest with a crossing place with no more than a Home Signal and Section Signal in each direction and it is obvious that the shunt will have to pass the Section Signal at danger to reach a siding connection which lies in advance of it, just the same could happen if there was an Advanced Starting Signal but again depending on its position in relation to the outermost/second Home Signal.  In other words the limiting point of the shunt movement will not necessarily be marked by a fixed signal - it simply proceeds only as far as is necessary to make the shunting move.  

 

So in fact providing an Advanced Starting Signal in order to accommodate shunting movements into a single line section actually serves no real purpose except possibly as a reminder to a Driver who might otherwise set off into the section without authority when shunting has finished.

 

Hope that makes it all a bit clearer and if you look at these diagrams on the SRS site (and click along to adjacent 'boxes you can get an idea of how teh Regulation would be used in order to shunt various sidings/yards

 

http://www.s-r-s.org.uk/html/gwa/T3010.htm

 

 

Edited to clarify what happens if there is more than one Home Signal

 

Edited September 11, 2017 by The Stationmaster

[Junctionmad]

Thanks stationmaster, so typically the shunt could , pass intermediate starters that are " on" and even the outermost starter , the advance starter could be passed at danger ? Without a token release.

 

So why was token request and token returned bell codes introduced ?

 

And what' happens if the shunt fouled the clearing point , yet I understand there is no blocking back inside the home bell for ETB.

 

So is it the intermediate starters , say like a platform starter would be pulled off , but the 3-3 is still given , and the train would pass the home ( in reverse direction ) but not the outer starter ?

 

What would happen if the home was outside the outermost starter ? ( which is the case in my case ) and the shunt needed to pass that starter but not the outer home

 

Would drivers pass starters at danger in a shunt move , I find that problematic

 

My understanding was that advanced starters were added to diagrams to specifically remove the need to release a token to shunt ahead , i.e. Shunting could now go as far as the advanced starter without token release. Wasn't this the reason they existed

Edited September 10, 2017 by Junctionmad

[phil-b259]

Thanks stationmaster, so typically the shunt could , pass intermediate starters that are " on" and even the outermost starter , the advance starter could be passed at danger ? Without a token release.

 

So why was token request and token returned bell codes introduced ?

 

And what' happens if the shunt found the clearing point , yet I understand there is no blocking back inside bell for ETB.

 

So is it the intermediate starters , say like a platform starter would be pulled off , but the 3-3 is still given , and the train would pass the home ( in reverse direction ) but not the outer starter ?

 

What wouod happen if the home was outside the outermost starter ?

 

If there are advanced starting signals and outer home signals then all shunting will take place within station limits and not the block section.

 

For example there is no need to get a single line token out or worry about blocking back at Sheffield Park thanks to the installation of an advanced starter (15) and an outer home (19) with 740 yards between them.

 

If however a shunt move has to take place past the outer home then either it must be done after the departure of a northbound service or a single line token will need to be issued.

 

In pre-preservation (or indeed the first few decades of Bluebell ownership) things were far simpler signalling wise and there were no such things as an advanced starter or outer home to facilitate shunting.

Edited September 10, 2017 by phil-b259

[Junctionmad]

If there are advanced starting signals and outer home signals then all shunting will take place within station limits and not the block section.

 

For example there is no need to get a single line token out or worry about blocking back at Sheffield Park thanks to the installation of an advanced starter (15) and an outer home (19) with 740 yards between them.

 

If however a shunt move has to take place past the outer home then either it must be done after the departure of a northbound service or a single line token will need to be issued.

 

In pre-preservation (or indeed the first few decades of Bluebell ownership) things were far simpler signalling wise and there were no such things as an advanced starter or outer home to facilitate shunting.

I have some issues here , yes I agree normally with outer homes and advanced starters no shunts go beyond the starter or set back in the rear of the home. ( mind you again , I have an issue where the advanced starter in both directions is inside the outer home, when does 3-3 apply rather then a token release to clear the advanced starter )

 

But , I can't agree with

 

If however a shunt move has to take place past the outer home then either it must be done after the departure of a northbound service or a single line token will need to be issued.

 

My understanding , as per station master is a shunt going beyond the home is a 3-3 , and the starter is effectively ignored

At no point would a token be released on backing through a home , that makes no sense , home signals don't release tokens ( so to speak ) , starters do ( if you get the meaning )

 

Again the issue is where the advanced starter is inside the outer home , and the shunt remains inside the home but outside the advanced starter, my view is in that case a token would be needed and 3-3 would not apply

Edited September 10, 2017 by Junctionmad

[ForestPines]

Thanks stationmaster, so typically the shunt could , pass intermediate starters that are " on" and even the outermost starter , the advance starter could be passed at danger ? Without a token release.

 

So why was token request and token returned bell codes introduced ?

 

And what' happens if the shunt fouled the clearing point , yet I understand there is no blocking back inside the home bell for ETB.

 

So is it the intermediate starters , say like a platform starter would be pulled off , but the 3-3 is still given , and the train would pass the home ( in reverse direction ) but not the outer starter ?

 

What would happen if the home was outside the outermost starter ? ( which is the case in my case ) and the shunt needed to pass that starter but not the outer home

 

Would drivers pass starters at danger in a shunt move , I find that problematic

 

My understanding was that advanced starters were added to diagrams to specifically remove the need to release a token to shunt ahead , i.e. Shunting could now go as far as the advanced starter without token release. Wasn't this the reason they existed

At Arley on the SVR these types of move are done regularly under rules derived from the old WR book. At the North end of the station the Down section signal is an Advanced Starting Signal, in advance (with respect to Down trains) of the Up Home signal, and most shunts at that end of the station do go outside the Up Home. Therefore the procedure (for, say, shunting from a platform road to the yard) is for the Signalman to get permission from the next box either by blocking back or releasing a token, then clearing the platform starter. The benefit of blocking back is that, as The Stationmaster said, the next box along the line could also be blocking back at the same time.

 

At the South end of the station there is no Advanced Starting Signal; the Starting Signal on the platform is the Section Signal. Shunting at this end is most often done when running round, when the section is occupied by a train travelling away. In this situation the shunt move can shunt behind the departing train, and is authorised to pass the Section Signal with a yellow flag. If the loco shunting is still outside the Down Home when the Signalman at the next box knocks out, then the Signalman must respond with 3-3 instead of acknowledging the 2-1.

 

There is no equivalent to blocking back inside the Home; when shunting you can occupy the line between the Home home and the Clearing Point freely as long as no train has been accepted or is in section (unless it has come to a stand at the Home or was accepted under Reg 5 of course. But in the context of Arley, Reg 5 can only be used in situations where its use is mandatory, in any case).

[Junctionmad]

 

 

At the South end of the station there is no Advanced Starting Signal; the Starting Signal on the platform is the Section Signal. Shunting at this end is most often done when running round, when the section is occupied by a train travelling away. In this situation the shunt move can shunt behind the departing train, and is authorised to pass the Section Signal with a yellow flag. If the loco shunting is still outside the Down Home when the Signalman at the next box knocks out, then the Signalman must respond with 3-3 instead of acknowledging the 2-1.

 

 

so what you are saying is that ETB regulations allowed a shunt into the next section to ignore the starter/section signal and pass it at danger ?

 

would therefore, in the case where the advanced starter is inside the outer home, also be that case, i.e. the shunt outside the starter would be authorised by hand , and the starter ignored, i.e. to a platform observer , a train went through a signal at danger !. 

 

 

i.e. if the train needed to shunt into section A, then infact no bell signals would be sent and all that would happen is the driver would be authorised to shunt past the AS at danger ?, its only if the shunt was to pass the OH, then 3-3 would be sent ?. I find it hard to believe a driver would pass an AS without a token ?

 

 

 

 

Signalman to get permission from the next box either by blocking back or releasing a token, then clearing the platform starter. The benefit of blocking back is that, as The Stationmaster said, the next box along the line could also be blocking back at the same time.

 

OK, so where he just blocked back, he couldnt pull off the platform starter ?, and also why would you release a token to clear the platform starter since its not the section signal ? , isnt it the case that the token release is electrically  locked to the AS ?

Edited September 10, 2017 by Junctionmad

[phil-b259]

My understanding , as per station master is a shunt going beyond the home is a 3-3 , and the starter is effectively ignored

At no point would a token be released on backing through a home , that makes no sense , home signals don't release tokens ( so to speak ) , starters do ( if you get the meaning )

 

Again the issue is where the advanced starter is inside the outer home , and the shunt remains inside the home but outside the advanced starter, my view is in that case a token would be needed and 3-3 would not apply

 

Sorry a typo crept in, I meant to say

 

"If however a shunt move has to take place past the outer home advanced starter then either it must be done after the departure of a northbound service or a single line token will need to be issued.

 

Again the issue is where the advanced starter is inside the outer home , and the shunt remains inside the home but outside the advanced starter, my view is in that case a token would be needed and 3-3 would not apply

 

 

Much depends on there attitude of the railway concerned (not permissible on the Bluebell, a token is always required when shunting past the advanced starter - with the exception of it being done after a departing train) but in principle I guess it could be done. As long as no token is issued for an opposing movement and the person in charge of the shunt goes no further past the advance than is necessary then it doesn't pose a safety risk. 

Edited September 10, 2017 by phil-b259

[Junctionmad]

 

 

Much depends on there attitude of the railway concerned (not permissible on the Bluebell, a token is always required when shunting past the advanced starter - with the exception of it being done after a departing train) but in principle I guess it could be done. As long as no token is issued for an opposing movement and the person in charge of the shunt goes no further past the advance than is necessary then it doesn't pose a safety risk. 

Thanks, I think in recent years ( post 72 ?) the trend has been to require a token release to pass an advance starter  for shunting ,  I wasn't aware of this regulation " with the exception of it being done after a departing train", thats an interesting one 

 

​I admit its an edge case because in the prototype  in my case distances were such that shunting would not have exceeded the AS in either direction ( AS's were added for precisely that reason)

 

​Howver in my model , space is constrained, so trains will need to pass the AS to shunt certain sidings , and I was wonder whether its a " howler " to release the AS or not ?

 

Final comment 

 

​Its been my experience that many token releases are locked to the advanced starter.  SO in the case of shunting past the AS following a departed train , The AS would not be pulled off for that move, in that case does the signalman hand signal the move past the AS ?

Edited September 10, 2017 by Junctionmad

[Junctionmad]

Could I summarise my understanding 

 

This is based on the  situation where the outer home is beyond the starter , i.e. the home is futher back on the single line 

 

 

1. you can shunt past the starter, without it being pulled off and no token is needed 

2. this can be done if a train has departed travelling away from you 

3. if your shunt takes you to the rear of the OH , 3-3 is exchanged 

4. if 2-1 is sent by the remote box, the box answers directly with 3-3 rathe then acknowledging the 2-1 , assuming the shunt is to the rear of the OH 

 

so on a model , it would be acceptable to shunt past the AS ,but not past the OH ( then a 3-3 is needed )  with the AS at danger ( where the AS is the signal the shunting train hits first !) 

Edited September 11, 2017 by Junctionmad

[ForestPines]

so what you are saying is that ETB regulations allowed a shunt into the next section to ignore the starter/section signal and pass it at danger ?

I can only speak of the current SVR ETT regs here. It is not explicitly addressed, but it is implied - the regs permit shunting into section in contexts where no token is released, the Section Signals are interlinked with the instruments, therefore a shunt into the section which requires a loco to pass a section signal must require the loco to be authorised to pass that signal at danger.

 

would therefore, in the case where the advanced starter is inside the outer home, also be that case, i.e. the shunt outside the starter would be authorised by hand , and the starter ignored, i.e. to a platform observer , a train went through a signal at danger !.

 

OH.jpg

 

That is a bit of an impractical layout - why would you put the Advanced Starting Signal there without giving enough room to shunt inside it?

 

i.e. if the train needed to shunt into section A, then infact no bell signals would be sent and all that would happen is the driver would be authorised to shunt past the AS at danger ?, its only if the shunt was to pass the OH, then 3-3 would be sent ?. I find it hard to believe a driver would pass an AS without a token ?

 

No, you have misunderstood there - any time a shunt passes the Advanced Starting Signal it is going into the section. The options available are:

 

* if there is a train in section A heading away from the signalbox, the shunt can be authorised to pass the signal and no bell codes can be sent

* if the Section is not occupied (or is only occupied by a blocking back move at the other end of the section) and no approaching train has been accepted the Signalman can block back and authorise the driver to pass the signal

* if the Section is not occupied and no approaching train has been accepted the Signalman can request a token be released for shunting and then clear the signal. The token is not given to the train crew.

 

OK, so where he just blocked back, he couldnt pull off the platform starter ?, and also why would you release a token to clear the platform starter since its not the section signal ? , isnt it the case that the token release is electrically locked to the AS ?

Something might have been unclear in my previous post; I was talking about a location which has an Advanced Starting Signal on the Down but only a Starting Signal on the Up. So in the latter case it is correct that you cannot pull off the Starting Signal when blocking back, as it is the Section Signal and therefore interlinked with the token instruments.

[ForestPines]

Could I summarise my understanding

 

This is based on the situation where the outer home is beyond the starter , i.e. the home is futher back on the single line

 

 

1. you can shunt past the starter, without it being pulled off and no token is needed

2. this can be done if a train has departed travelling away from you

3. if your shunt takes you to the rear of the OH , 3-3 is exchanged

4. if 2-1 is sent by the remote box, the box answers directly with 3-3 rathe then acknowledging the 2-1 , assuming the shunt is to the rear of the OH

 

so on a model , it would be acceptable to shunt past the AS ,but not past the OH ( then a 3-3 is needed ) with the AS at danger ( where the AS is the signal the shunting train hits first !)

I think you may have a couple of things conflated here. I'll try to summarise:

 

You are shunting into section if you pass *either* the section signal *or* the outermost Home for approaching trains.

 

If the outermost Home is in advance of the Section Signal then there may well be a local instruction prohibiting shunting into section.

 

If there are no local instructions otherwise, there are three ways of shunting into section.

 

1) By shunting behind a departing train. In this instance no bells are exchanged unless the other Signalman knocks out whilst the Section is obstructed, in which case the 2-1 is answered by 3-3 which the other Signalman acknowledges.

 

2) By blocking back.

 

3) By releasing a token.

 

In cases 1 and 2, if the shunt has to pass the Section Signal and that signal is interlinked with the token instruments, then self-evidently the shunt must be authorised to pass that signal at Danger.

[Junctionmad]

Tks , that's all clear

[phil-b259]

​Its been my experience that many token releases are locked to the advanced starter. SO in the case of shunting past the AS following a departed train , The AS would not be pulled off for that move, in that case does the signalman hand signal the move past the AS ?

Correct (ish) - the proper term would be that the driver was 'authorised to pass the advance starter at danger but only by as much as is necessary to perform the shunt move. Current Bluebell rules dictate that permission must be obtained on every occasion rather than giving permission for as long as the shunting takes. This reinforces the idea that passing any stop signal when 'on' requires permission but also allows for the the previous train having reached the other end of the token section (thus allowing a token to be issued for shunting) or for the shunting to stop so as to allow another train to be accepted from the far end of the block section under reg 4.

[The Stationmaster]

Thanks stationmaster, so typically the shunt could , pass intermediate starters that are " on" and even the outermost starter , the advance starter could be passed at danger ? Without a token release.

 

Any intermediate stop signal in rear of the Section Signal could be cleared for the movement if necessary and provided it was otherwise legitimate to do so.  But yes the Section Signal - be it Starter or Advanced Starter could be passed at danger without the need to release a token

 

So why was token request and token returned bell codes introduced ?

 

For use in those situations where a token would be required.  This would usually be the case where the token was needed to release a ground frame.

 

And what' happens if the shunt fouled the clearing point , yet I understand there is no blocking back inside the home bell for ETB.

 

The shunt would have started from within the Clearing Point in any event if it is a setting back movement from one side of a crossing loop (i.e. a train has arrived in the crossing loop and then sets back to shunt a siding in rear of the Home Signal which it has just passed).   But you need to take account of the Clearing Point in ETT Regulations being somewhat different from the Clearing Point in Double Line Absolute Block because the very way in which a single line crossing loop has to be worked in order to cross trains means that Train Out of Section is sent while an arriving train is standing within the Clearing Point provided it is wholly within its appropriate loop.

For what would amount to a shunt frward the fact that the movement will go outside the Home Signal for the opposite direction means it is inevitable that it will foul the Clearing Point in advance of that signal.

 

This does however need a correction to an ambiguity inmy initial reply which should have been checked more carefully instead of my rushing off - late - to dinner.  I have corrected it above but the critical point is that the 3-3 is used (and the same other movement conditions apply) if the shunt will go outside 'the second Home Signal where and additional signal is provided'  - i.e. it is still within an additional Home Signal which has been provided 440 yards in rear of the second Home Signal in order to create a Clearing Point

So is it the intermediate starters , say like a platform starter would be pulled off , but the 3-3 is still given , and the train would pass the home ( in reverse direction ) but not the outer starter ?

 

The train, actually a shunt move and not necessarily a train, can go as far as is necessary to make the shunt and no further  irrespective of any fixed signals.   It doesn't matter if it passes the Section Signal - wherever that signal happens to be - the key things is that it passes the relevant Home Signal (in the opposite direction of course)

 

What would happen if the home was outside the outermost starter ? ( which is the case in my case ) and the shunt needed to pass that starter but not the outer home

 

See above - depending on which Home Signals are involved - the position of the most advanced Starting Signal (the Section Signal) is irrelevant.  The shunt simply passes that signal at danger.

 

Would drivers pass starters at danger in a shunt move , I find that problematic

 

Why - it happened everyday of the week in the steam/early diesel age age over many years without incident but as I noted in some places where the move was regular (e.g. engine run round at Chipping Norton) a Shunt Ahead subsidiary was used.  On one occasion I set-back a 10 coach passenger train onto single of necessity past a signal at danger because there happened to be a previously departing train in the section.  Like many things on the railway if it is done responsibly by those who know what they're doing it is safe.  If it was risk assessed using modern methodology but taking into account historical data the incidence figure would come out very low indeed as would the consequences number.  There were instances where drivers carried on gaily into the single section but again the consequences were relatively limited.  The risk would clearly not be ALARP by modern standards - which would mean providing a fixed signal to limit the shunting movement and totally eliminate any risk other than a SPAD - but not far short of it in absolute terms.

 

My understanding was that advanced starters were added to diagrams to specifically remove the need to release a token to shunt ahead , i.e. Shunting could now go as far as the advanced starter without token release. Wasn't this the reason they existed

 

The only advantage an aAdvanced Starting Signal provides is that it might act as a visible limiting point fora shunting movement.  But there's no reason why a shunt could not proceed past it if circumstances so required and there's no reason why an Advanced Starting Signal could not have a Shunt Ahead subsidiary (as some actually did e.g. Cookham).  But it was still a Shunt Outside the Home Signal - that is, again, the critical point so therefore the 3-3 would still need to be sent if the shunt is not following a train proceeding into the section or after ToS has been received for that train.

One important point you need to remember is that many heritage/preserved railways have signalling installed which is way excessive compared with what might have originally been there and they apply variations in their Signalling Regulations which didn't exist back in BR days.  This is where outermost Home Signals at least 440 yards in rear of the Section Signal in the opposite direction have developed as something to provide full fixed signal provision to limit shunting movements while still allowing trains to be accepted in the opposite direction (probably the case at Sheffield Park and definitely the case at Buckfastleigh - see the 'box diagram below).  This has no doubt happened in order to increase operational flexibility and cater for significantly more movements than was the case on most single lines in past years

 

Arguably this arrangement is less safe than the old Regulation as it permits two movements to proceed towards each other on the single line and relies entirely on Drivers not passing a signal at danger - so immediately we move from a situation where one Driver might have made an error with little risk of a subsequent collision to one where there are two Drivers relied upon not to make an error with the potential for a head-on collision if either of them errs. Thus both the potential and consequences elements in any risk assessment will worsen.

 

[Junctionmad]

One important point you need to remember is that many heritage/preserved railways have signalling installed which is way excessive compared with what might have originally been there and they apply variations in their Signalling Regulations which didn't exist back in BR days. This is where outermost Home Signals at least 440 yards in rear of the Section Signal in the opposite direction have developed as something to provide full fixed signal provision to limit shunting movements while still allowing trains to be accepted in the opposite direction (probably the case at Sheffield Park and definitely the case at Buckfastleigh - see the 'box diagram below). This has no doubt happened in order to increase operational flexibility and cater for significantly more movements than was the case on most single lines in past years

 

 

 

Arguably this arrangement is less safe than the old Regulation as it permits two movements to proceed towards each other on the single line and relies entirely on Drivers not passing a signal at danger - so immediately we move from a situation where one Driver might have made an error with little risk of a subsequent collision to one where there are two Drivers relied upon not to make an error with the potential for a head-on collision if either of them errs. Thus both the potential and consequences elements in any risk assessment will worsen.

 

IMGP7039cr.jpg

Thank you very much

 

I model Irish railways in the 70s as well as WR based club layouts. Your last comment is interesting as it formed the basis for a collision in the 70s at Rosslare strand where AS and OH were added and a train was also accepted under warning . The inspectors report makes interesting reading

 

CIE at that stage were changing from the 1950s RCH rule book to the 1972 BR one

 

( which added a provision to require 3-3 if shunting between OH and inner homes as well

[Junctionmad]

This does however need a correction to an ambiguity inmy initial reply which should have been checked more carefully instead of my rushing off - late - to dinner. I have corrected it above but the critical point is that the 3-3 is used (and the same other movement conditions apply) if the shunt will go outside 'the second Home Signal where and additional signal is provided' - i.e. it is still within an additional Home Signal which has been provided 440 yards in rear of the second Home Signal in order to create a Clearing Point

 

 

Do you mean where a shunt occurs between an inner and outer home , a 3-3 bell would be exchanged ( except if following a departing train

[The Stationmaster]

Do you mean where a shunt occurs between an inner and outer home , a 3-3 bell would be exchanged ( except if following a departing train

 

Exactly so.  The important factor - implied by the title of the Regulation - is that the shunt is going onto the single line (even though it could potentially still be within Station Limits).  Thus the reference to 'the second Home Signal' effectively means the one at the end of the single line and protecting the turnout to the loops etc.   I think it would have been extremely unlikely in the past to have come across many signalboxes with more than one other stop signal in rear of that signal but where that was the case the Signalbox Special Instructions would suitably expand the Regulation to make very clear which signal it applied to.

 

The only advantage in providing an additional Home Signal at a single line crossing station for acceptance purposes in the past would literally be for that purpose alone  and nothing else  and would in reality be more or less pointless other than at a junction or terminus.   The important factor here is that the normal double line 440yards Clearing Points did not apply at single line crossing stations meaning a train could be accepted as long as the crossing loop to which it would run was clear from the Home Signal to the signal at the advance end of that loop.

[Nearholmer]

Probably a daft question, with a blindingly obvious answe, but one that has bugged me for a while:

 

Given what you've just said, what is the point in having both a home and a starter, which is a very typical arrangement, at such a crossing point? Wouldn't one signal, positioned where the started is typically positioned, be sufficient?

 

I'm assuming in asking this, that any overrun of the signal would be effectively trapped.

 

Kevin

Edited September 13, 2017 by Nearholmer

[Ray H]

The home signal protects the points at that end of the crossing location whereas the starting signal performs to (usual?) act as the section signal.

 

There are many loops where there are no traps at the advance end of the station which is why trains are only allowed to enter the station one at a time in those situations.

[Nearholmer]

OK ....... so it's because:

 

- there is no interlocking between the granting of authority to enter the section, and the setting of the points at the 'arrival' end; and,

 

- the home is used to ensure that the train is controlled down to a speed that makes it very unlikely to overrun the section signal, before it is admitted to the loop, because there is no trap if it does overrun.

 

Did I get that right?

 

And, this absence of trapping is common??

Edited September 13, 2017 by Nearholmer

[RailWest]

The home signal protects the points at that end of the crossing location whereas the starting signal performs to (usual?) act as the section signal.

 

There are many loops where there are no traps at the advance end of the station which is why trains are only allowed to enter the station one at a time in those situations.

Correct on both counts :-) Indeed, I would suggest that trap-less version is/was by far the more common arrangement - not only cheaper to install and maintain, but facing points in passenger lines were usually avoided as far as possible.

 

Conversely, in a 'light railway' scenario it was not uncommon to find passing-loops with only Homes, the authority to start away into the next section being given verbally by the signalman (or whoever was doing the equivalent job) when handing over the staff/tablet/token for the next section.

[The Johnster]

OTOH the GW was keen on traps, which are re-assuring in their ability to physically keep traffic separated.  It was one of the matters in which it felt superior to 'lesser; railways, which usually managed to avoid collisions nonetheless.  

[RailWest]

OTOH the GW was keen on traps, which are re-assuring in their ability to physically keep traffic separated.  It was one of the matters in which it felt superior to 'lesser; railways, which usually managed to avoid collisions nonetheless.  

I would disagree. Although there were a lot of loops on the GWR with traps, in general they tended to be either for speeding up the services (eg the Barnstaple and Minehead branches), or for safety reasons such as severe gradients etc (and then more as a protection against 'break aways' on unfitted goods trains).

 

The Stationmaster may have other views? :-)