Quick question on a terminus signal box

[Lacathedrale]

If I have a box at the mouth of a  terminus, I can understand that there will be down outer home/home signals inbound to the station, and then in return will be platform starters and advanced starters leading out. However, if there is a distant signal on one of the advanced starters, that represents the block AFTER the block that the starter is gating entry to - right? I.e. it would be controlled by the next signal box along, representing that signal box's onward area of control (rather than representing the block between the advanced starter and the home signal of the next box) - is that right?

[Peter Kazmierczak]

If I've read this correctly, then "yes" it is. The distant would be controlled by the next signalbox along, indicating that the forward section is clear.

[RailWest]

Maybe .....it all depends :-) For example, the  distant might be just for a level-crossing ground-frame somewhere in the block section.

 

In simple (?) terms:-

 

The block section for trains leaving the terminus (A) would extend from its most advanced starting signal to the outermost home signal at the next box (B). That distant to which you refer would be worked by the next box B (probably - see above). Clearance of that distant by box B would only be possible when all his stop signals were off for the road ahead to the next box C, ie the block section from B to C is also clear. In that respect therefore clearance of the distant (at A) would reflect the state of the block between B and C, tho' really it is more importance to the driver of the train leaving A as it tells him that he has a clear run through B.

 

Of course, a distant worked by B would only exist under a signal at A anyway if A and B were close together (say less than a mile or so).

 

 

[Lacathedrale]

Thank you both, that's really great to hear. I am specifically referring to the latter example in RailWest's post.

 

Along those lines, when would B set the distant? I read that it would be interlocked to be on unless A's starter was off - and that wouldn't happen until B has accepted a train from A, and A has set the starter.

[RailWest]

B can not pull off his distant until ALL his stop signals on the relevant route are 'off'. He can not pull off his most advanced starting signal until his has got a 'Line Clear' acceptance from C. When he pulls the lever for his distant, whether the arm actually comes off or not depends on the 'slot' mechanism on the signal post which ensures that it will not clear until A's stop signal above it is 'off'.

 

But out of curiosity, you seem to be assuming that B will have a distant under a signal at A - why?

[Flying Pig]

The normal sequence, assuming both B and C can accept the train would be

 

- A offers the train to B who accepts and gives "line clear"

- A clears his starter; B's distant remains at caution

- since the section is short and so as not to delay the train, B immediately offers the train to C who also accepts and gives "line clear"

- B clears all his stop signals and then his distant

 

So the distant clears a short time after A's starter and before the train has departed A. The train departs with both arms at clear.  After the train has passed it, A puts his starter back to danger and the slotting ensures that B's distant returns to caution at the same time. 

 

Othetwise, if C cannot accept the train before it leaves A (for example, because there is still a preceding train in the section B-C, or C is at a junction and a train is signalled on the other line) then B cannot clear his starting signal or his distant.  The train departs A with the starter at clear and B's distant at caution.   Once the train has gone  and A returns his starter to danger, the slotting will prevent the distant arm from clearing even if B subsequently pulls the lever for it, so you never see the starter at danger with the distant arm showing clear.  Note that in this case, the driver must assume that the signals at B are at danger until they come into sight and drive the train at reduced speed so as to be able to stop if necessary. 

 

But as RailWest said, 

 

2 hours ago, RailWest said:

Of course, a distant worked by B would only exist under a signal at A anyway if A and B were close together (say less than a mile or so).

 

so you are assuming a short section between A and B

[bécasse]

Actually that wouldn't necessarily be the sequence at a busy terminal. The bell signals would take place in the sequence described and the points necessary for the route would be set by the terminal box, but at busy terminals the actual signals wouldn't be cleared until the box got the TRTS indication from the platform foreman. That was done so that if a problem occurred the layout wouldn't be locked up by the already cleared signals.

I was sometimes allowed (under supervision and after I had satisfied the SM that I knew all the relevant rules and regulations - and how to use hook switches and short-circuiting bars) to work part of the frame at a major London terminal during the evening peak hour. The only "mistake" I ever made was to once pull off without awaiting the TRTS light - I was only about 90 seconds early and yet the driver was straight on the blower wanting to know why he already had a double yellow. Fortunately the SM answered the phone and as soon as he spoke, I heard the voice at the other end say "oh, it's you guvner, yes I will await the right away". It was a lesson in the practicalities of train operation that was instantly learnt, it wasn't in the Rule Book nor in the Regulations nor even in the box local instructions, but it was still a golden rule that kept the railway running. I learnt a few other useful lessons too, not least the importance of team working and reacting immediately to potential emergencies. I never did master pulling three miniature levers simultaneously with one hand but the regular men could, and did, all do it.

[Lacathedrale]

Wow, thank you all so much - very exhaustive.

 

Becasse, how would this have worked in the (19)20's? I assume a similar process but probably not with a button! 

 

Flying Pig, thank you - this is exactly my thought. In my notional railway A (terminus on layout) and B (somewhere in the fiddle yard) will be close enough  that B's distant would be on A's starter. For yourself and Railwest, With regard to the slotting of B's distant - does this mean that he would be unable to clear it, or that if he did clear it the position of A's starter would 'hold' it at caution until that was cleared too?

 

Overall, this seems like a little fun addition to a terminus layout that would otherwise be purely shuffling trains. I'm not sure about the idea of using full size machines, but in general operational signals combined with a call and return of signalmen between two operators seems pretty fun. 

[ejstubbs]

24 minutes ago, Lacathedrale said:

With regard to the slotting of B's distant - does this mean that he would be unable to clear it, or that if he did clear it the position of A's starter would 'hold' it at caution until that was cleared too?

 

To prevent B from clearing his distant if A's starter was on - i.e to lock B's lever in place - you'd have to have interlocking between the boxes.  In practice the "interlocking" was done at the signal post, using a mechanism that stopped the arm of B's distant from moving until A's starter had been cleared, even if B had pulled the lever for his distant.  There's quite a good diagram of such a mechanism on page five of this LMS Society "monologue" paper.

[Lacathedrale]

Excellent, that's perfect! If it's not too much of a pain I have a few supplementary questions which are related more to signalling rather than signalboxes:

 

• Shunt operations within the limit of the home and advanced starter (as opposed to platform starters) would not require individual shunting signals on the platforms, would they?
• In the other direction, would there be calling-on signals for the platforms (for example, for a station pilot to back up to coaches from an inbound tender loco)? If so, where would they be located? I got the impression that the home would be a single semaphore arm - but not sure about anything between that and the platforms themselves! (for the sake of argument, a station with five roads (i.e. a couple of platform faces, a couple of sidings)
• For other movement around the station area I can imagine ground signals for sidings and protecting any movement from a siding/goods line that would bring it onto a passenger line, I gather the latter would be routed to the signalbox rather than as a ground frame?

 

Edited April 2, 2019 by Lacathedrale

[RailWest]

>>>>In my notional railway A (terminus on layout) and B (somewhere in the fiddle yard) will be close enough  that B's distant would be on A's starter..

 

As you say, it's your national railway - but if there was no perceived reason on your imagined prototype for the next signal-box up the line to be quite so close to the terminus, then why bother to add the complication of having to model the distant and its associated slotting at all?

[The Stationmaster]

4 hours ago, Lacathedrale said:

Excellent, that's perfect! If it's not too much of a pain I have a few supplementary questions which are related more to signalling rather than signalboxes:

 

• Shunt operations within the limit of the home and advanced starter (as opposed to platform starters) would not require individual shunting signals on the platforms, would they?
• In the other direction, would there be calling-on signals for the platforms (for example, for a station pilot to back up to coaches from an inbound tender loco)? If so, where would they be located? I got the impression that the home would be a single semaphore arm - but not sure about anything between that and the platforms themselves! (for the sake of argument, a station with five roads (i.e. a couple of platform faces, a couple of sidings)
• For other movement around the station area I can imagine ground signals for sidings and protecting any movement from a siding/goods line that would bring it onto a passenger line, I gather the latter would be routed to the signalbox rather than as a ground frame?

 

Depends to some extent on era modelled and owning company plus any particular operational but -

 

1.  There is normally no need for subsidiary shunt(ing) signals beneath the platform Starting Signals for movements towards the Advanced Starting Signal.

2.  In some installations by the 1920s Calling On subsidiary signals would have been used but - again depending on Company - there were plenty of places where they didn't exist and there was of course no formal requirement to provide them (e.g my local GWR three platform terminus, did not having any Calling On Signals until the 1950s despite being extremely busy at times).

Some sort of indicator, or a multipicity of arms, would be used to signal movements to more than one platform - practice varied between Companies and locations.

3. Probably but it depends how far the points would be (in real world equivalent) from the signalbox; again practice could vary between Companies.

[Lacathedrale]

Thanks very much again Chris and Mike, it's very kind of you to take the time to answer me!

[Lacathedrale]

29 minutes ago, RailWest said:

>>>>In my notional railway A (terminus on layout) and B (somewhere in the fiddle yard) will be close enough  that B's distant would be on A's starter..

 

As you say, it's your national railway - but if there was no perceived reason on your imagined prototype for the next signal-box up the line to be quite so close to the terminus, then why bother to add the complication of having to model the distant and its associated slotting at all?

 

"Because it's there", George Mallory 1923 

 

I haven't even got close to applying saw to wood, but to properly site my layout in a place and time, with interactions beyond the four borders is pretty important for my childlike brain!

[Flying Pig]

Slotted distants look pretty and are the only distants most of us have space to model.

 

29 minutes ago, Lacathedrale said:

I haven't even got close to applying saw to wood, but to properly site my layout in a place and time, with interactions beyond the four borders is pretty important for my childlike brain!

 

I absolutely agree. If you aren't modelling an actual location, a well-imagined hinterland is vital to achieving a credible setting and operation.