Two-box stations / Slotted “stop” signals

[Drummle]

I’ve been trying to get my head around the signalling arrangements at stations governed by more than one signal-box. I think (famous last words) that I understand the principles, but I’d be grateful for any help putting them into practice!

 

The first two diagrams below show what I think would be a fairly normal set-up in which the box in rear (“West”) has its starter signal slotted with the home signal of the box in advance (“East”). Black sections show the block controlled by each box, and green sections are station limits.

 

Is it correct that the East box (in advance) has no actual block under control, and thus that “Is Line Clear?” posed from West to East relates only to the ¼-mile overlap in advance of the East home signal? Or to put it another way, that West could run a train up to the East home without consulting East at all?

 

In my mind the West starter / East home signal is slotted at the post just like a home/distant signal, thus the starter lever at West could be pulled but the arm would remain “on”. In that scenario would the West signaller be required to observe rule 39(a) and caution a train at their own home signal, and would this rely on their attentiveness to the actual position of the starter/home arm or maybe a reminder device? Or am I completely wrong and there would actually be some kind of mechanical interlock between the boxes themselves so that the starter lever couldn't be pulled until East had pulled their home lever? Maybe this is situation specific, thinking about it.

 

(In the diagrams I’ve showed slotted signals with the arm showing the most “urgent” restriction in the horizontal position but I’m not sure if that's correct. The distinction in the RSSB guidance previously shared on this forum seems to be between “slotted by” another box and “slotted at” another box which is clear as mud to me!)

 

If I’ve got things right so far, then I guess that in the above example (considering only the West box now) that a loco headed “up” from West to East could run around its train under the control of the ground signals A and B and head off back down-line without troubling the signaller at East.

 

On the other hand it wouldn’t be permitted for the loco to pass the West starter (aka East home) before reversing unless there was a special instruction to allow working in the wrong direction back into East’s (zero-length!) block, and presumably special interlocking / acceptance levers? (I guess this is what acceptance levers are for, I’ve seen them on SB diagrams but never understood their purpose without being able to cross-reference the local rules of course.)

 

Finally before my head explodes, would a scenario like this be practical? Again the signals shown as “active” are controlled from the West box, and although it looks contrived in isolation(!), in effect the platform road here is just like a bidirectional platform in a larger station (or the “back road” at e.g. Ely).

 

As I see it the East signaller can safely pull off his starter (which is actually a slot on both arms of West’s down home as shown – I guess one lever would suffice for this) and thus give a train the right away into the reversible platform! Part of me feels like this must be wrong as there “ought” to be a token or suchlike before a train can be released into a bidirectional track, but is it actually all ok because that track is entirely within West’s station limits and the signal doesn’t actually clear until West is good and ready and has also pulled a lever?

 

Hopefully some more knowledgeable than me can help here, and if so many thanks in anticipation! I’ve been a longtime lurker on here and am always in awe of the expertise on offer…

 

Sam

Edited October 22, 2021 by Drummle
Correction

[Nick C]

I think you've got the overlap between them in the wrong place. Looking at the first pair I can find on the SRS website, which hapens to be Polegate Junction west and east, it's the signal before the platform that is slotted by both boxes, not the one after - so going from east to west along the main line, you first reach east box's home signal, then his starter, which is also west box's home, then east box itself, then the station, then west box's starter, then west box. (terminology may vary here, as all the signals on that route are in rear of the box controlling them, so for some companies, they would all be homes)

[LNERGE]

I'm shuddering to think of the wires and slots involved in some of this. Obviously it is all possible and it was done regularly. I had to cheat when i 'modelled' the back platform at Ely as i didn't have enough levers/one end controlled by a Westinghouse L frame. I put all the controls in the block.

 

https://www.wbsframe.mste.co.uk/public/Ely_Dock_Junction_L_Frame.html#

Edited October 22, 2021 by LNERGE

[RailWest]

What about the alternative, where the block section is actually the stretch of line past the platform? In other words, the 'Home' at the entrance to the platform is West's 'section signal' for the line to East, and the 'Starter' at the exit from the platform is actually East's Home signal. Neither signal would be slotted by both boxes.

[Wheatley]

Railwest has it. The block section is the bit from the last controlled stop signal of one box to the first controlled stop signal of the next box. Station limits is the first to the last of the same box.

 

In your first diagram West has no station limits and the block section is the green bit. 

 

Stations do not have to be within Station Limits, and Station Limits do not have to have to have a station in them. To assume otherwise is a modellerism. 

 

For a real life example look at Barnsley before resignalling in 1998. Both platforms were within block sections, both boxes had SL on one line but not the other, and neither box's SL had a station in it. My down home/section signal at Jumble Lane was slotted by Barnsley Station Junction but that was because the facing points for the junction to Penistone were in his Clearing Point, not because the sections were short. I don't think Jumble had a slot for BSJ's up home/section signal.  

[micknich2003]

Here is an example of "Slotted Signals", up to the mid '30's there were further slots on Flemingate signals which was then a Block Post.

[Drummle]

On 22/10/2021 at 22:45, Wheatley said:

Railwest has it. The block section is the bit from the last controlled stop signal of one box to the first controlled stop signal of the next box. Station limits is the first to the last of the same box.

 

In your first diagram West has no station limits and the block section is the green bit. 

 

Stations do not have to be within Station Limits, and Station Limits do not have to have to have a station in them. To assume otherwise is a modellerism.

Thanks for this (also to Chris). (I’m afraid I’m not sufficiently au fait with the railway geography of Barnsley to understand the other use of slotting you outline, but I think that is quite a different purpose so will leave that be!) Here’s an amended diagram as per your explanation and without modellerisms (I hope).

 

I do understand that there's the alternative of having the platforms in the block section rather than within station limits, but didn't think this would be applicable when the platform is operated bi-directionally as in my second two examples? Having thought some more, though, this is how I think “B” would now look:

 

In the specific case of an “up” train being run-around in the station, I assume that it would be accepted into the block by East as normal; the engine would detach and East would advise West “Engine Arrived” before sending the loco back down the loop, which is now a second block operating in the opposite direction. But how would the loco then be signalled back into the platform (which is now a block occupied by the carriages of the train), though? This is why I’d assumed the platform had to be within somebody’s station limits in this case.

 

The same question applies in my example C (below), with the addition that the platform road itself is reversible; and thus I guess would have to be fully protected by tokens etc.? (The complete layout would have a trailing connection into the up main from a branch, so the reversibility is necessary.)

 

 

Thanks again for the thoughts so far, every day really is a school day!

Sam

 

[Drummle]

Thanks for the diagrams Mick. I still can't make head nor tail of when to use which of the following!

 

But at least I've learned something...

[RailWest]

In all the above new examples, the 'Up Starter' at the START of the platform IMHO is superfluous, as all moves into the platform could be controlled by the stop signal in rear or a shunt signal at the Down line end of the crossover.

 

Likewise in C1 and C2, as there appears to be no pointwork or other potential obstructions between the Down Home and Down Starter, then one of those is superfluous also.

[Drummle]

19 minutes ago, RailWest said:

In all the above new examples, the 'Up Starter' at the START of the platform IMHO is superfluous, as all moves into the platform could be controlled by the stop signal in rear or a shunt signal at the Down line end of the crossover.

 

Likewise in C1 and C2, as there appears to be no pointwork or other potential obstructions between the Down Home and Down Starter, then one of those is superfluous also.

Thanks, so helpful.

 

On the up side, makes sense to remove the West starter. Still not sure how the shunt into the occupied platform block could be authorised though!

 

On the down side of C, the East down home positioned where it is means a wrong line move to run around would be blocking back inside rather than outside the home. Naïvely I'd expect that to be preferred but maybe not? Perhaps depends only on whether traffic is dense enough to make the option for East to accept traffic from further up-line under the Warning Arrangement?

[The Stationmaster]

First there is/was no problem at all in having  a station platform in a block section that was bi-directional because it is simply signalled as a single line section using whatever method would be suitable for such a line.  Not particularly common but not impossible.  Shunting in either direction was very common but was covered by other procedures so the line would not be signalled as a single line for that purpose.  

 

Don't forget that it was quite common to have a signal box at each end of stations if the track layout so required and teh distance between signal box and the points it was permitted to operate left no alternative.  At many smaller locations gradual relaxation of the distance allowed between signal boxes and the points they worked allowed the location to be reduced to a single 'box and much of this went on in the 1930s in order to reduce the wages bill.   But even at some relatively straightforward double line stations two signal, around a quarter of a mile or so (or less) apart survived into the 1960s.  And of course numerous parts of the Signalling regulations made provision for closely spaced 'boxes and the signals they worked.

 

Secondly running an engine round a train which s. is standing in a block section is a very straightforward procedure which could be done in any double line Absolute Block section provided that it was not specifically prohibited (usually because of gradients although sometimes various other reasons might apply).  On a single line there is/was no similar Regulation for the simple reason that you cannot run round a train which is in a single line section as there is no other line for the engine to use (although a through siding might exist).  Thus if there was a need for such a procedure it would normally be covered in the signal Box Special Instructions although I can't immediately think of anywhere that it would have happened.

[5BarVT]

Paignton N and S existed a platform length apart right up to Exeter resignalling.  The down line was unidirectional but the up line was bidi. PS could switch out to allow a simple ‘turnback’ DMU service to be operated just with PN but opened up whenever loco hauled run round and Goodrington sidings were required.  There were two sets of block instruments, I think one for each line.

Paul.

[The Stationmaster]

20 hours ago, 5BarVT said:

Paignton N and S existed a platform length apart right up to Exeter resignalling.  The down line was unidirectional but the up line was bidi. PS could switch out to allow a simple ‘turnback’ DMU service to be operated just with PN but opened up whenever loco hauled run round and Goodrington sidings were required.  There were two sets of block instruments, I think one for each line.

Paul.

Interestingly the Sectional Appendix shows both lines simply as Absolute Block but it seems that Interlocking Levers were used in order to prevent conflicting signals from being cleared. (back to Cheltenham and elsewhere where Interlocking Levers were used. ).

[RailWest]

7 hours ago, The Stationmaster said:

Interestingly the Sectional Appendix shows both lines simply as Absolute Block but it seems that Interlocking Levers were used in order to prevent conflicting signals from being cleared. (back to Cheltenham and elsewhere where Interlocking Levers were used. ).

IIRC - but I would need to check and that could take some time - there was the normal set of AB instruments for Down trains on the Down line and Up trains on the Up line, plus another instrument for trains going wrong-direction on the reversible line.

[Drummle]

On 26/10/2021 at 12:18, The Stationmaster said:

Don't forget that it was quite common to have a signal box at each end of stations if the track layout so required and teh distance between signal box and the points it was permitted to operate left no alternative.  At many smaller locations gradual relaxation of the distance allowed between signal boxes and the points they worked allowed the location to be reduced to a single 'box and much of this went on in the 1930s in order to reduce the wages bill.   But even at some relatively straightforward double line stations two signal, around a quarter of a mile or so (or less) apart survived into the 1960s.  And of course numerous parts of the Signalling regulations made provision for closely spaced 'boxes and the signals they worked.

This is exactly the scenario I'm considering and given how common it was it's surprising how little there discussion there is in the various online sources of the situation! If I ever come to feel authoritative enough maybe I'll put a page up myself, but that's clearly not yet...

 

I believe that the other reason for this arrangement would be (on busy lines) to allow the signaller at the relevant end of the station to give "train out of section" at the start of the station stop on sight of the tail lamp — if there were only one box then a train approaching from the opposite end of the station could not be given "out of section" until it had completed its stop and the tail lamp had passed the box.

 

On 26/10/2021 at 12:18, The Stationmaster said:

First there is/was no problem at all in having  a station platform in a block section that was bi-directional because it is simply signalled as a single line section using whatever method would be suitable for such a line.  Not particularly common but not impossible.  Shunting in either direction was very common but was covered by other procedures so the line would not be signalled as a single line for that purpose.

Would you mind elaborating on "whatever method"? Was/is there an alternative to the use of train staff or token operation that would be more suitable for this situation? I have seen diagrams featuring "acceptance levers" which I guess have something to do with it?

 

On 26/10/2021 at 12:18, The Stationmaster said:

Secondly running an engine round a train which s. is standing in a block section is a very straightforward procedure which could be done in any double line Absolute Block section provided that it was not specifically prohibited (usually because of gradients although sometimes various other reasons might apply).  On a single line there is/was no similar Regulation for the simple reason that you cannot run round a train which is in a single line section as there is no other line for the engine to use (although a through siding might exist).  Thus if there was a need for such a procedure it would normally be covered in the signal Box Special Instructions although I can't immediately think of anywhere that it would have happened.

Would you mind explaining how this would be done or referring me to the relevant regulation if it's available online?— I am stumped at step 5 in the below.

1 Train comes to a stand in the block between [A] and : block instrument shows "train on line"

2 Loco pulls forward to 's station limits; gives "engine arrived" and instrument remains at "train on line"

3 Loco uses pointwork at to change lines and returns to [A] in the usual way

4 Loco uses pointwork at [A] to return to the original line

5 ??? Loco now needs to enter the block between [A] and which already has a "train on line"!

6 Train exits the section in the opposite direction at [A]

7 [A] signals "train withdrawn" and returns block to normal ("line blocked")

 

Many thanks again

Sam

[Michael Hodgson]

Regulation 11 is the rule applicable to running around a train within section.  Your step 5 is similar to the procedure when a loco has to attach a vehicle (eg a horse box, buffet car, parcels van) to the rear of a train, in that the move is generally authorised by a shunt signal or a call-on subsidiary signal (short arm under a main running arm).   The signalman in rear must have received Engine Arrived (2-1-3) before he is allowed to clear this signal.  This obviously doesn't arise as an issue if it's the same engine taking the train back, but it is important to avoid misunderstadnings where a different engine is doing the return journey so you don't want both locos moving at the same time.

 

You could also need to apply Regulation 32 (Working in Wrong Direction) should the engine have to return in the wrong direction, which might be the case in a bogger station.  Regulation 31(Shunting into Forward Section) can apply in some cases.

 

It's better explained here ...

https://signalbox.org/block-system/shunting/

[5BarVT]

2 hours ago, Drummle said:

5 ??? Loco now needs to enter the block between [A] and which already has a "train on line"!

I assume that you have access to some version of the block regulations or, at least, a list of bell codes.

As the block is still at Train on Line, it is the Permissive Working Arrangements that apply.  Where authorised (i.e. it’s expected to happen) Is Line Clear can be sent with the block at TOL and accepted by 2-4-2 Line Occupied Acceptance.

The loco is signalled into the section with a Calling On signal or a Green hand signal from the box. (The regs talk about clearing the main signal, but with Line Clear block controls that won’t happen.)

2 hours ago, Drummle said:

7 [A] signals "train withdrawn" and returns block to normal ("line blocked")

Remember, it’s not [A] that is controlling the block on that line, so [A] sends Train Withdrawn and responds with Train Out of Section and places the block to Normal (Line Blocked).  (I can’t find the reference to this just at the moment but I’m sure I’ve read it earlier today!)

 

Paul.

Edited October 29, 2021 by 5BarVT

[5BarVT]

12 minutes ago, Michael Hodgson said:

Regulation 11

Thank you Michael, I knew I’d read it somewhere!

Paul.

[beast66606]

On 25/10/2021 at 18:57, Drummle said:

Thanks for the diagrams Mick. I still can't make head nor tail of when to use which of the following!

 

But at least I've learned something...

 

The one to the left is when the box controls the slot on another boxes signal, the one on the right is when the signal is controlled by the box but slotted by another box. On the LM the slot symbol would be smaller than the main arm

[Michael Hodgson]

... and on the Western, the arms would be lower quadrant !

[bécasse]

Not just on the Western. Well into BR days, many signal box diagram linens, from which the display prints were produced, were updated originals dating back before 1930 when upper quadrant signals were all but unknown and thus showed lower quadrant signals even though the real things had been converted to UQ (or replaced by UQ signals). In fact, it wasn't unusual to find linens that dated back to the pregrouping era.

[RailWest]

Nor was it unusual for LQ arms to survive well into the 1960s anyway on place such as the ex-L&SWR and S&DJR.

[5BarVT]

And one at Leicester that survived into the 80s.

Paul.

[The Stationmaster]

15 hours ago, 5BarVT said:

I assume that you have access to some version of the block regulations or, at least, a list of bell codes.

As the block is still at Train on Line, it is the Permissive Working Arrangements that apply.  Where authorised (i.e. it’s expected to happen) Is Line Clear can be sent with the block at TOL and accepted by 2-4-2 Line Occupied Acceptance.

NO!  the run round is covered by Absolute Block Regulation 11 and would apply between any two signal boxes, irrespective of the length of the block section between them unless the 'Box Instructions specifically prohibited its use.  You can'tr use Permissive Block bell signals or procedues iona line signalled by Absolute Block except where particular provision applies and even you would not use when applying Regulation 11.

15 hours ago, 5BarVT said:

The loco is signalled into the section with a Calling On signal or a Green hand signal from the box. (The regs talk about clearing the main signal, but with Line Clear block controls that won’t happen.)

Remember, it’s not [A] that is controlling the block on that line, so [A] sends Train Withdrawn and responds with Train Out of Section and places the block to Normal (Line Blocked).  (I can’t find the reference to this just at the moment but I’m sure I’ve read it earlier today!)

 

Paul.

Yes.

[The Stationmaster]

20 hours ago, Drummle said:

This is exactly the scenario I'm considering and given how common it was it's surprising how little there discussion there is in the various online sources of the situation! If I ever come to feel authoritative enough maybe I'll put a page up myself, but that's clearly not yet...

 

I believe that the other reason for this arrangement would be (on busy lines) to allow the signaller at the relevant end of the station to give "train out of section" at the start of the station stop on sight of the tail lamp — if there were only one box then a train approaching from the opposite end of the station could not be given "out of section" until it had completed its stop and the tail lamp had passed the box.

The main reason for having more than one signal box was the permitted maximum distance between a signal box and the points it operated.  In addition an additional 'box (or possibly a gate box which was not a block post) might have to be provided to operate. a level crossing which was not readily overseen by a signal box with concentrations of pointwork too far from it.   Nobody ever provided more than one signal box for the sheer fun of - it all depended on money and the cost of operation which was usually more expensive than the cost of actually building the second 'box (or multiple further examples).  Sometimes there would be 'boxes separately provided to control the Up, Down, or fast and whatever, sections of a large/complex track layout.  And long block sections 'out in the country' might be split by a 'break section' 'box in order to increase line capacity

 

The track layout and the 'boxes came first and then the Regulations were gradually devised or revised to suit situations where block sections were short or the stop signals operated by two (or more) successive 'boxes were less than a certain distance apart.

 

If it was considered an aid to the working of a particular location the rearmost 'box at, or approaching, a busy station might - where possible - be provided with an Acceptance Home Signal (i.e an additional Home Signal serving no other purpose) which moved its Clearing Point rearwards and thus allowed 'Train out of Section' to be given, and the block cleared,  once the train had passed beyond the Clearing Point although that train might still be in Station Limits or it had entered a short section in advance.  Unless there was a specially authorised Clearing Point (instead of the usual 440 yards) in normal working no 'box could give 'Train Out of Section' for a train until that train had passed 440yds beyond the outermost Home signal and the Signalman had observed or had been advised (where authorised) that it was complete with tail lamp.  The only exception to this in normal working would be at 'boxes authorised to accept trains under the Warning arrangement (Regulation 5 as once was) in which case the Signalman would send the 2-1 bell signal but would hold the block at 'Train On Line' pending being offered a train that he was allowed to accept under the Warning

20 hours ago, Drummle said:

 

Would you mind elaborating on "whatever method"? Was/is there an alternative to the use of train staff or token operation that would be more suitable for this situation? I have seen diagrams featuring "acceptance levers" which I guess have something to do with it?

If it was for train working Acceptance Levers or Interlocking Levers, or track circuits, or interlocking block instruments, could be used instead of the more traditional methods of working a single line.  For shunting in most cases trains would enter a section for shunting purpose and then withdraw from it and usually anything going through a section while shunting would proceed in the right direction over a suitable line.  In some cases a through siding might be used and in some cases where regular wrong direction shunts went through a section Interlocking Levers might be used but generally protection was effectively given by the Signalling Regulations and the Rules

20 hours ago, Drummle said:

 

Would you mind explaining how this would be done or referring me to the relevant regulation if it's available online?— I am stumped at step 5 in the below.

1 Train comes to a stand in the block between [A] and : block instrument shows "train on line"

2 Loco pulls forward to 's station limits; gives "engine arrived" and instrument remains at "train on line"

3 Loco uses pointwork at to change lines and returns to [A] in the usual way

4 Loco uses pointwork at [A] to return to the original line

5 ??? Loco now needs to enter the block between [A] and which already has a "train on line"!

6 Train exits the section in the opposite direction at [A]

7 [A] signals "train withdrawn" and returns block to normal ("line blocked")

 

 

I'm not sure if there is anything on line and I haven't looked online at the current Block Regulations for some time.  The former ABR 11 became part of Regulation 3 after the 1985 revision of the Block Regulations (I was a member of the working group for that revision) and as it stood in the 1990s reissue it was part of AB Regulation 3 as 3.11.  But the procedure then was, odd differences from the modernisation of wording apart, no different from ABR 11 in the 1960 and 1972 issues of the Block Regulations and in its essentials no different from RCH AB Regulation 10A as stood in the 1930s or indeed RCH AB Regulation 10A as it stood in 1920.  

ABR = Absolute Block Regulation)

 

As far as the part you have numbered as Step 5 is concerned the situation is simple as the engine would be crossing from the opposite line there would probably be a ground disc for the movement plus verbal instruction from the Signalman at the 'box in rear of the train.  there is no need for any block bell signalling as it is all part of the one process of running round something which has been block signalled into the section and which is still there.  All very straightforward and no doubt done countless times over the years at many stations or indeed in block sections where there weren't any stations.

20 hours ago, Drummle said:

 

Many thanks again

Sam