Verification of signal placement please.

[Titanius Anglesmith]

Great answer, very informative. Thanks

[meil]

I suspect the Station Master is underestimating the use of Blocking Back on heritage railways.

 

Obviously if a token can be obtained then that should be done but Blocking Back is a regular occurrence on our railway, usually in the context of BB behind departing train, where 3-3 is only sent in the event that the departing train is 2-1.

 

Of course it must be remembered that 3-3 cannot be sent if a train has been accepted because that acceptance has established that the clearing point is unobstructed (and will remain unobstructed) and the route set and locked. To undertake the shunt would therefore violate the conditions of acceptance.

[phil-b259]

2 minutes ago, meil said:

I suspect the Station Master is underestimating the use of Blocking Back on heritage railways.

 

Obviously if a token can be obtained then that should be done but Blocking Back is a regular occurrence on our railway, usually in the context of BB behind departing train, where 3-3 is only sent in the event that the departing train is 2-1.

 

Of course it must be remembered that 3-3 cannot be sent if a train has been accepted because that acceptance has established that the clearing point is unobstructed (and will remain unobstructed) and the route set and locked. To undertake the shunt would therefore violate the conditions of acceptance.

 

I'm not sure he is.

 

For example the Bluebell has provided advanced starters and outer homes since the early 1980s and has not used blocking back since then while recent resignalling on the Mid-Hants has seen the addition of advance starters + outer homes too. The latter railway definitely started out with what you might say 'basic signalling' to get things running - but as the railway got busier the reliance on 'blocking back' and other such rules started to cause incidents and operational problems on busy days

 

Although 'blocking back' is perfectly fine when done correctly, reliance on it is frowned upon in official circles as correct implementation is entirely down to people getting things right. With fixed signals (interlocked with each other and the taken block) extra protection against mistakes is provided.

 

As the head of the ORR made clear some time ago, he REQUIRES the Heritage Railway sector to deliver the 1950s visitor experience with 21st century levels of safety. Simply relying on humans to obey written rules is generally not considered sufficient these days, particularly if the task is undertaken on a semi-regular basis as complacency can set in.

 

Thus the signalling on many Heritage Railways has ended up being far more comprehensive than was installed in British railways days - and this should be reflected in an Heritage Railway model set in the past couple of decades (Naturally if you are modelling a fledgling railway in the mid 1970s then everything, including the signalling, will be a bit more basic).

[The Stationmaster]

4 hours ago, phil-b259 said:

 

I'm not sure he is.

 

For example the Bluebell has provided advanced starters and outer homes since the early 1980s and has not used blocking back since then while recent resignalling on the Mid-Hants has seen the addition of advance starters + outer homes too. The latter railway definitely started out with what you might say 'basic signalling' to get things running - but as the railway got busier the reliance on 'blocking back' and other such rules started to cause incidents and operational problems on busy days

 

Although 'blocking back' is perfectly fine when done correctly, reliance on it is frowned upon in official circles as correct implementation is entirely down to people getting things right. With fixed signals (interlocked with each other and the taken block) extra protection against mistakes is provided.

 

As the head of the ORR made clear some time ago, he REQUIRES the Heritage Railway sector to deliver the 1950s visitor experience with 21st century levels of safety. Simply relying on humans to obey written rules is generally not considered sufficient these days, particularly if the task is undertaken on a semi-regular basis as complacency can set in.

 

Thus the signalling on many Heritage Railways has ended up being far more comprehensive than was installed in British railways days - and this should be reflected in an Heritage Railway model set in the past couple of decades (Naturally if you are modelling a fledgling railway in the mid 1970s then everything, including the signalling, will be a bit more basic).

Very much the case Phil and thanks for drawing attention to it.  And yes one very real proliferation of signals on the busier (and some times less busy) preserved/heritage lines is the appearance of additional Home Signals (what in non WR speak are called Outer Home Signals) plus Advanced Starters to provide, respectively, no need to shunt outside the Home Signal into the section, and a very clear limiting point for shunting moves.  In some cases these preceded the ORR taking greater interest in safety on such railways and it is worth remembering that the level of traffic and frequency of trains on soe of these lines is way in excess of what they saw back on BR or p=Pre-Nationalisation days.

 

In the past couple of decades HMRI has fortunately at long last taken a g far greater level of interest in all aspects of safety on these railways with one important outcome being to try to wean people off use of the old BR, black cover, 1950 Rule Book which is totally inadequate for today's safety requirements.  The Block Signalling regulations - Rule Book references apart - are generally still reasonably well suited to heritage railway train signalling needs although inevitably over complicated in some respects because a lot of stuff just isn't needed on a heritage railway.

[Michael Hodgson]

On 10/04/2020 at 10:40, The Stationmaster said:

Basically yes.  Done under what was at one time Block Regulation 7 (on Electric Token Lines) 'Occupation of the Single Line for shunting or Engineering Purposes'.  This was a procedure where a Signalman could send a 3-3 bell signal (in a similar manner to Blocking Back on double line) to make a shunt 'outside' the outermost Home Signal, i.e. into the single line section after the Signalman at the other end of the section had acknowledge the 3-3 bell signal.  The presence or otherwise of a Starting or Advanced Starting Signal was irrelevant in the context of this Regulation - what mattered was the fact that the movement would be made outside (i.e. to in rear of) the Home Signal and therefore into the single line section - which ended at the outermost Home Signal.  This latter point seems to be the one that many people miss - the critical part is a movement into the single line section and technically that ends (and in effect also commences) at the Home Signal and not at any Starting Signals.

 

 

 

I don't visit this site as often as I should, so I must apologise for not answering  questions that were raised following my earlier post, but I am pleased to see others have already addressed them.

 

I agree with most of the above quote, but it does raise an interesting and rather subtle point.  On double track, "station limits" runs from the  home to the starter, and the section runs thence to the next set of station limits, so they alternate: section, station, section...  The home signal for one line need not be (and usually isn't) opposite the starter the other way, but that doesn't matter as they are separate lines.  Where an outer home signal exists, that is the boundary and an overlap extends as far as the inner home.

 

Applying the same principle to a single line I would agree that the section for an arriving train ends at the home (outer home if it exists) of the next box in that direction and similarly in the other direction, but if you worked from the starter that would mean the incoming and outgoing sections wouldn't quite coincide unless the signals happened to be opposite one another (as was perhaps the case where they were on the same post).  So on single lines, station limits extends between from the outer home signal in each direction.

 

As you say Regulation 7 says you need to block back if you want to occupy the single line beyond the home signal, but there is also an introductory clause which says where an additional home signal is provided, the second home is to be regarded as the home signal for the purposes of this regulation.  I am open to correction this but I take it to mean you also need to block back if you are going beyond the Inner home but still within the outer home.  It's within station limits, but also within the overlap, which I see as the approximate equivalent of Blocking Back Inside Home Signal as used on a double track line but not applicable to single lines.  

 

 

[RailWest]

>>>As you say Regulation 7 says you need to block back if you want to occupy the single line beyond the home signal, but there is also an introductory clause which says where an additional home signal is provided, the second home is to be regarded as the home signal for the purposes of this regulation.  I am open to correction this but I take it to mean you also need to block back if you are going beyond the Inner home but still within the outer home....

 

I have always found the reference to 'second home' somewhat ambiguous and confusing. Logically I would argue that the 'additional home' is the 'second home', as the block section then starts/ends at the outer home so why would you need to block-back if you are only going outside the inner home, but still inside the outer home? On the other hand, especially in an LMS context, for an approaching train surely the 'second home' is the one that you come to after the first home?

[The Stationmaster]

13 hours ago, Michael Hodgson said:

 

I don't visit this site as often as I should, so I must apologise for not answering  questions that were raised following my earlier post, but I am pleased to see others have already addressed them.

 

I agree with most of the above quote, but it does raise an interesting and rather subtle point.  On double track, "station limits" runs from the  home to the starter, and the section runs thence to the next set of station limits, so they alternate: section, station, section...  The home signal for one line need not be (and usually isn't) opposite the starter the other way, but that doesn't matter as they are separate lines.  Where an outer home signal exists, that is the boundary and an overlap extends as far as the inner home.

 

Applying the same principle to a single line I would agree that the section for an arriving train ends at the home (outer home if it exists) of the next box in that direction and similarly in the other direction, but if you worked from the starter that would mean the incoming and outgoing sections wouldn't quite coincide unless the signals happened to be opposite one another (as was perhaps the case where they were on the same post).  So on single lines, station limits extends between from the outer home signal in each direction.

 

As you say Regulation 7 says you need to block back if you want to occupy the single line beyond the home signal, but there is also an introductory clause which says where an additional home signal is provided, the second home is to be regarded as the home signal for the purposes of this regulation.  I am open to correction this but I take it to mean you also need to block back if you are going beyond the Inner home but still within the outer home.  It's within station limits, but also within the overlap, which I see as the approximate equivalent of Blocking Back Inside Home Signal as used on a double track line but not applicable to single lines.  

 

 

It is difficult to apply the normal principle of  Station Limits in the normal way to a single line crossing station because the single line section effectively lies between the two opposite Home signals protecting the single to double connection.  To add some further complication at most single line crossing stations there was never a 440 yard Clearing Point either so effectively you couldn't do a 2-4 Block Back (Blocking Back Inside Home Signal).  Thus the only Blocking Back Signal would inevitably have to be for a movement outside (i.e. in rear of) the Home Signal.  

 

Where an additional Home Signal is provided at a crossing station in theory it would be feasible to have a 2-4 Block Back (and it is mentioned in the bell signals in the SR Block Regulations but not in the actual Regulation!) .  I suspect nobody ever bothered with a Regulation for blocking back inside because additional Home Signals were rare on single lines and if necessary the situation could be covered in the Signal Box Special Instructions.  Thus the Regulations have only referred to the 3-3 bell signal.  However such a movement would obviously foul the Clearing Point but not necessarily pass beyond the outermost Home Signal but it is protected by that signal.

 

It is perhaps easy to forget, or not to have come across the fact that places such as various West of England branch termini with very heavy summer traffic and in some cases considerable shunting of coaching stock never had additional home signals.  Even with heavy seasonal traffic and longer trains there was no need to spend money on such signals, even when locking frames were renewed and other capacity enhancing work took place - the need simply didn't exist.  And although Exmouth had them on both approach routes they were obviously needed there for acceptance purposes towatds the junction

 

In signalling terms the 'additional Home Signal' is the always the one additionally provided for (usually) acceptance purposes,  and described in the Regulations as 'the outermost Home Signal'.  Thus on a single line the 3-3 has to be sent and acknowledge for a movement which will be made outside the protection of that signal.  The term  'additional Home signal' clearly originated because it added something that the original, and essential, Home Signal did not.  What has no doubt confused later  students over the years is the multiplicity of terms used to describe this signal some of which relate to its purpose and some of which are rather more nebulous.  Added to which even the railway Companies changed things about over the years.  Thus a common term for such a signal describes their purpose - provided they are at least 440yds in rear of the next stop signal in advance and they are referred to as 'acceptance home signals' - more of a vernacular description than one used in the Regulations.  Commonly they are termed Outer Home Signals but the GWR rather logically stopped calling them that some time between the two wars and henceforth called them 'Home Signals' which at least simplified explanations in various Regulations.  On the LMS/BR, LMR they at some time became  described as 'Home 1' with each successive stop signal in advance of them numbered upwards until they became Starting signals.

[bécasse]

4 hours ago, The Stationmaster said:

And although Exmouth had them on both approach routes they were obviously needed there for acceptance purposes towards the junction.

Actually I suspect that there may well have been other reasons why Exmouth was provided with the additional homes which are now lost in the mists of time.

 

Meldon Junction was the convergence of two single lines from the west but there the use of the warning arrangement was authorised to overcome acceptance problems rather than the provision of additional homes. Despite regular use of the arrangement, warning signals weren't provided at the preceding stations either, making them one (two?) of the few places on the Southern where you could regularly see a signalman display a green flag to "warn" a train.

 

It may be, of course, that they were provided at Exmouth simply because a new box was being provided and the necessary levers could readily be included in the specification, certainly the signalling provision at the rebuilt station was quite generous.

[The Stationmaster]

16 hours ago, bécasse said:

Actually I suspect that there may well have been other reasons why Exmouth was provided with the additional homes which are now lost in the mists of time.

 

Meldon Junction was the convergence of two single lines from the west but there the use of the warning arrangement was authorised to overcome acceptance problems rather than the provision of additional homes. Despite regular use of the arrangement, warning signals weren't provided at the preceding stations either, making them one (two?) of the few places on the Southern where you could regularly see a signalman display a green flag to "warn" a train.

 

It may be, of course, that they were provided at Exmouth simply because a new box was being provided and the necessary levers could readily be included in the specification, certainly the signalling provision at the rebuilt station was quite generous.

I think they came with the new 'box and the lavish layout it served.  Quite a good location as a basis for a layout providing good operational interest.

[RailWest]

Do not forget that, after the closure of Lympstone as a block-post, Exmouth got an extra 'additional home' (No 10) apparantly specifically to allow acceptance of a train from Topsham while shunting was in progress at Exmouth on the 'main' line out towards the Up Advanced Starting.

[Jeremy Cumberland]

On 10/04/2020 at 11:38, meil said:

Obviously if a token can be obtained then that should be done but Blocking Back is a regular occurrence on our railway, usually in the context of BB behind departing train, where 3-3 is only sent in the event that the departing train is 2-1.

Excuse my ignroance; I haven't had much to do with blocking back. Does this mean that the other signalman isn't told at all about the move into the section until the first train has cleared it? Does the other signalman return the token to the instrument then (assuming single line working with tokens)?

 

From your post, I imagine the sequence for shunting into the section behind a departing train to be this, but surely it cannot be right:

1. Box A obtains line clear from Box B and withdraws token
2. Train departs A and Box A sends train entering section to Box B
3. Shunt onto single line commences at A, under the control of Box A
4. Train arrives at B
5. Box B sends out of section to Box A and returns token to instrument
6. Box A sends blocking back to Box B and withdraws token
7. On completion of shunting at A, Box A sends cancelling to Box B and returns token to instrument

I had thought that 3-3 would need to be sent by Box A and acknowledged by Box B before the shunt commenced (ie between steps 2 and 3), although I had always wondered what reminder Box B might have not to return the token to the instrument, also whether there would be cofusion between Box B sending 2-1 and Box A sending 3-5, which presumably could happen in either order.

[RailWest]

Steps 1 to 5 basically correct.

6: A sends 3-3, which B must acknowledge as clearly the shunt is already underway. NO token is withdrawn - that's the whole purpose of BB, it avoids the need to withdraw a token.

7. A sends 2-1 'Obstruction Removed' not 3-5.

[Jeremy Cumberland]

Thank you. What bell codes are sent at steps 5 and 6? Does Box A answer Box B's 2-1 with 3-3 or does Box A reply 2-1 and then send 3-3? If the latter, does box A send call attention before sending 3-3?

 

What aide memoires, if any, do the signalmen use? Does either signalman place a collar on the starter lever, for example?

[The Stationmaster]

At step 5 Box B sends Call Attention to Box A and after that is acknowledged sends 2-1, Train Out of Section, to Box A which is also acknowledged and B puts the token into his token machine. 

At step 6 Box A sends Call Attention to Box B and after this is acknowledged he sends 3-3 to Box B which is acknowledged by repetition.

 

On the WR prior to December 1966 the Call Attention bell signal was not sent prior to sending the Train Out of Section bell signal.

 

Most Signalmen in my experience didn't bother with aide-memoires in these situations because they had the indicator on the token instrument and (hopefully) their Train Register book was up-to-date.  All depends also on the era because by the 1950s in many places the section signal was in any case released by withdrawal of the token at the 'box which worked it but only for one pull so couldn't be cleared anyway.  If you were doing a 3-3 block back on double lines on the Western you could always use the reminder flap pn the block instrument but again I doubt many Signalmen bothered.

 

Shunting onto a single line came in a variety of circumstances.  Your post above covered one of them where a shunt was made behind a departing train (I've only been involved in doing it just once).  Far more common was simply the need to make a shunt into the section when no other trains were about and of course the Regulations allowed that to be done at both ends of a single line section at the same time i.e. there were two shunts in the section at one and the same time.  As ever with making a shunt into a section there were local restrictions - normally as a result of gradients - while in some places it took place so frequently subsidiary Shunt Ahead signals were provided (e.g Chipping Norton where it was necessary to shunt onto the single line in order for the engine of arriving passenger trains to run round).

[Michael Hodgson]

If we're saying the outer home is the second home for the purposes of this regulation, this must have been ambiguous when used on BR(LMR).  Or did they only use the terms Home 1, Home 2 on double lines?

 

It sounds as though what we are saying is to do a shunt on a single line

 

(1) Get a token if the section is clear, using Release Token 5-2, Token Restored 2-5 when you're clear.  Give token to driver.

 

(2) if A has to shunt behind the departing train to B, permit it, driver doesn't get a token.  Use 3-3 if the train arrives before the shunt is clear.   Whilst it would have been possible to get a token now, there would be no point as the driver is already away shunting.  If the shunt is complete before Train Out 2-1, there is no need to block back.

 

It's 2-1 Train out of section from B to A for the train, but same bell code 2-1 Obstruction Removed from A to B for the block back.

 

(3) if B has to shunt whilst  3-3 is in force from A, B also can send 3-3, so both ends have to send Obstruction removed when finished.

He can also do this if 5-2 is in force from A.

 

(4) if the type of instrument (some staff instruments and IIRC, Tyers no 3 Tablet) doesn't allow the token to be replaced at the same end, you can't use Release/RestoreToken so again you have to use 3-3 Blocking Back/2-1 Obstruction removed instead.

 

 

Just to complicate things a bit further, under Train Staff and Ticket, where you presumably also have the same definitions of section and home signal, the rules DID provide for 2-4 Blocking Back Inside before the 1960 BR rule book came in.  This was required if a train has to come to a stand within the home signal but foul of the 1/4 mile beyond the home.  With this method of working you had block instruments as with used on double lines, so there was no token to request.   The GWR also had 1-2-3 Blocking Back for Train already in Section, used if you need to shunt outside home signal before Train Out of Section has been given. 

 

The GWR didn't require Train out of Section 2-1 to be acknowledged.  Some other companies rule books called for 2-1 to be acknowledged by a single beat rather than repetition.  Certain types of instrument require an additional plunge to be given after particular operations to bring the indicators at both ends into sync.

 

In many cases I suspect the practice with arriving trains was just to wait until the loco had run round or wagons detached etc before sending Train Out of Section. 

 

 

 

[RailWest]

AIUI - and no doubt Stationmaster will correct me if wrong :-) - when shunting into forward section you did not withdraw a staff/token/tablet (even if you could) unless it was needed specifically for the purpose of the shunt ie to unlock a GF at siding in the section. Otherwise, why bother, when Blocking Black would be sufficient to permit and protect the shunt?

[The Stationmaster]

17 hours ago, Michael Hodgson said:

If we're saying the outer home is the second home for the purposes of this regulation, this must have been ambiguous when used on BR(LMR).  Or did they only use the terms Home 1, Home 2 on double lines?

 

It sounds as though what we are saying is to do a shunt on a single line

 

(1) Get a token if the section is clear, using Release Token 5-2, Token Restored 2-5 when you're clear.  Give token to driver.

 

(2) if A has to shunt behind the departing train to B, permit it, driver doesn't get a token.  Use 3-3 if the train arrives before the shunt is clear.   Whilst it would have been possible to get a token now, there would be no point as the driver is already away shunting.  If the shunt is complete before Train Out 2-1, there is no need to block back.

 

It's 2-1 Train out of section from B to A for the train, but same bell code 2-1 Obstruction Removed from A to B for the block back.

 

(3) if B has to shunt whilst  3-3 is in force from A, B also can send 3-3, so both ends have to send Obstruction removed when finished.

He can also do this if 5-2 is in force from A.

 

(4) if the type of instrument (some staff instruments and IIRC, Tyers no 3 Tablet) doesn't allow the token to be replaced at the same end, you can't use Release/RestoreToken so again you have to use 3-3 Blocking Back/2-1 Obstruction removed instead.

 

You have missed the simplest option of all which is to use a 3-3 Block Back to shunt into the section.  No problem at all using it particularly where Shunting Tokens were not provided so it would come in the first/ second position in your list.   In the 1960 regulations the use of the 3-3 Block Back was actually the preferred method - in reality recognising what the situation had been at most places for many years.

In No.2 in your list there was never any requirement to draw a token - the movement was considered to be protected by the 3-3 Block Back 

You can only use a 3-3 Block Back, simultaneously at both ends of the section.  The Regulations (both GWR and BR did not provided for a 3-3 Block Back to be used at the opposite end of a section if a Shunting Token was being used at the other end and they very obviously prohibited the use of a 3-3 Block back at the opposite end of the section if an ordinary token had been withdrawn for shunting purposes.

 

Quote

 

Just to complicate things a bit further, under Train Staff and Ticket, where you presumably also have the same definitions of section and home signal, the rules DID provide for 2-4 Blocking Back Inside before the 1960 BR rule book came in.  This was required if a train has to come to a stand within the home signal but foul of the 1/4 mile beyond the home.  With this method of working you had block instruments as with used on double lines, so there was no token to request.   The GWR also had 1-2-3 Blocking Back for Train already in Section, used if you need to shunt outside home signal before Train Out of Section has been given. 

 

What you have described about the way in which a 2-4 Block Back was applied in the  TS&T Block Regulations is not correct,   A 2-4 Block Back had to be put on under TS&T Regulations in exactly the same manner as one would be applied in the double line Block Regulations, i.e before a stationary obstruction, or an obstruction which would become stationary, was allowed to foul the Clearing Point (including in the case of the GWR removal of a rail within the Clearing Point).  A 2-4 Block Back would not be used for a train which had come to a stand within the Clearing Point because the block should still be at 'Train On Line' and the 'Train out of section' bell signal would not have been sent - and of course it would a be physical impossibility to send it from a crossing location on a single line because trains could not then be block signalled to cross each other!   The 2-4 Block Back in the Train Staff & Ticket Block Regulations Regulations was discontinued from those former Company Block Regulations which had included it up to that time when the BR 'standard'(ish) Block Regulations took effect in 1960.  

 

There was not a reissue of the Rule Book in 1960 - that came in 1972; the 1950 Book had been reprinted to apply from 1 January 1962 incorporating any amendments which had been made up October 1961.  The reissue of any operating document such as a Rule Book is a completely different, and far simpler,  procedure than a reissue and the latter was only resorted to when significant alterations had n been made.  I can tell you from the experience of being involved in the process in later years that deciding which to apply is something which used to be given very careful consideration because of the wider legal implications. 

 

The BR Block Regulations replaced the former Company Block Regulations in 1960 and the General Appendix (also replacing previous Company issues )- which contained the single line Regulations other than the Signalling Regulations - were reissued to apply from 01 October  1960.  Interestingly Train Staff & Ticket Block Regulations did not appear in the WR version of the 1960 Block Regulations which would indicate that there was such limited use of them on the WR at that time that it wasn't worth including them in the book of Black Regulations (that was the standard procedure when reissuing any of the Rules & Regulations publications - it didn't necessarily mean a Regulation had ceased to exist but simply that if it did survive its application was so limited it could be covered in a different way such as Signal Box Special instructions).

 

The GWR dispensed with the 1-2-3 bell signal on single lines worked by Electric Token from January 1924 after it had been established that very little use was made of that bell signal.    It remained in use in the WR Double Line Block Regulations until August 1965.

 

.   

Quote

 

The GWR didn't require Train out of Section 2-1 to be acknowledged.  Some other companies rule books called for 2-1 to be acknowledged by a single beat rather than repetition.  Certain types of instrument require an additional plunge to be given after particular operations to bring the indicators at both ends into sync.

 

In many cases I suspect the practice with arriving trains was just to wait until the loco had run round or wagons detached etc before sending Train Out of Section. 

 

 

 

The requirement to acknowledge the 'Train Out of Section' bell signal by repetition applied on the WR from August 1965.

Edited August 26, 2020 by The Stationmaster