Pencarrow: nothing to see, move along please.

[The Stationmaster]

Chris you need the Home Signal (edit to clarify - just a straight post with a single arm, no bracketed arm, see below) in rear of the trap (actually it would be a slotted joint as SE has already said) and you also need an Advanced Starting Signal immediately in rear of it for departing trains in order, mainly, to detect that it is closed for departing train.

 

What I would also do is copy the original but with a bit of relocation and resite your existing splitting Home Signal where you have the second Home with the co-located ground disc - so it's now tight in your visible scene .

 

The only question mark then is how the connection to the mineral branch would be signalled - i.e. would it be done with semaphore arms or - as you currently have - with ground discs?  In my view (but it's you railway) this is where you need to led as much by appearance as by LSWR practice because using a semaphore splitting signal at the platform end might start to visually overwhelm the scene (and get even more in your way when viewing from one side/operating from the other) but if you went fora  co-located disc as per your sketch you could use a semaphore coming off the branch if you prefer the look of it.

 

So a bit of choice, a bit of wriggle room but easy enough to getting it looking absolutely right.

 

Edited to hopefully clarify (I did say 'hopefully')

Edited February 16, 2017 by The Stationmaster

[Donw]

Mike would you mind clarifying something it the splitting signal is located at the turnout for the loop as we both suggested would you still need the disc signal?

 

Don 

[2ManySpams]

The Goods Shed side looks close to the original. The connection leading onto the branch would need an FPL.

 

Not having signals on the Engine Release would not be unusual in most places but some far-flung bits of the network did have strange customs.

 

The catch point by the Starter would be worked as a Slotted Joint, so for an incoming it would work line an ordinary spring point but it would be held closed by pulling a lever in the box and provided with an FPL.

 

How is it intended to work the Wenford Branch? Is it a running line belonging to the 'Main Line' railway or a Private Siding? This will determine the positioning and type of signals required.

 

Eric

 

Thanks Eric much appreciated, I'm revising my sketch as I work through the comments received. 

 

I've added a FPL to the branch connection - that's an easy one. You might have to explain 'Slotted Joint' a bit further using the art of mime or mickey mouse sketches though as it's not something I'm familiar with! but I think I've worked out the need for a FPL on the home catch/trap. 

 

Very good question about the Wenford branch working as it's purely fictional. I'm fairly sure though it would be worked as a single long siding, one engine in section. Not sure how / if that answers your question?

[2ManySpams]

OK, i've not altered the signal types yet but have moved those right of the bridge to be the correct side of the catch. FPLs have been added as discussed. This is where i'm up to: 

 

 

I've also added some numbers (for trackwork) and letters (for signalling) to aid further description. 

 

Could I ask Eric, Don and Mike to confirm which signals need altering / moving using these references please??

 

Continued thanks all. 

[TheSignalEngineer]

I don't know the distances on the prototype but I think I have the explanation for the shunt arm on the outer home. If a train was signalled up to the home signal and buffered up coming to a stand the wagons would then ease back due to the gradient. As the catch point is not worked by the box unless a train was signalled onto the branch it would spring to the open position under the train. There is a risk of derailing because of this (been there, seen it happen) so an incoming train going into the loop or siding would be signalled by clearing the shunt signal at the inner home the the outer home. A shunt between sidings and the loop or platform would not go outside the starting signal so the single line section would be protected as the catch pout would be left in the sprung open position while this move took place.

 

Eric

Edited February 16, 2017 by TheSignalEngineer

[TheSignalEngineer]

I will try to find a picture of a slotted joint. The principle is that the catch point is sprung as normal and works in the usual way when trailing through it. The rod has an elongated hole so that the point can do this but when the lever is pulled it moves the point to the closed position and holds it there so it can be used in the facing direction.

 

Eric

[2ManySpams]

I will try to find a picture of a slotted joint. The principle is that the catch point is sprung as normal and works in the usual way when trailing through it. The rod has an elongated hole so that the point can do this but when the lever is pulled it moves the point to the closed position and holds it there so it can be used in the facing direction.

Eric

So a variation on a FPL then?

[TheSignalEngineer]

Slotted joints were used in both running and shunting situations. They worked like a conventional point in one direction and if for a passenger move an FPL would be provided.

[2ManySpams]

Slotted joints were used in both running and shunting situations. They worked like a conventional point in one direction and if for a passenger move an FPL would be provided.

There's discussion of catch, trap and slotted points here:

 

http://www.lner.info/forums/viewtopic.php?t=11003

 

Today is a school day.

[The Stationmaster]

OK, i've not altered the signal types yet but have moved those right of the bridge to be the correct side of the catch. FPLs have been added as discussed. This is where i'm up to: 

 

ScreenHunter_430 Feb. 16 20.21.jpg

 

I've also added some numbers (for trackwork) and letters (for signalling) to aid further description. 

 

Could I ask Eric, Don and Mike to confirm which signals need altering / moving using these references please??

 

Continued thanks all. 

 

Chris,

 

Noting SE's comment about running back on the gradient I make the following comments on the assumption that the overbridge will be the end of the scenically modelled area plus the fact that in reality any shunting confined inside the Advanced Starting Signal © would still need something for the divergent route at Signal D.

 

So I think you have a series of choices all of which would be 'right' should anyone care to examine them.  My original proposal was to put a straight post Home Signal at B and move the B as you have drawn it to position D thus giving you the chance to include an interesting looking signal within the modelled area.  The alternative would be to leave it as it is on your latest sketch and that would be wholly justified by what SE has said (and you could also assume that a similar format signal then exists at both B & D).  IT is I think as much a chance to do a bit of what you want as be governed by the exact prototype situation.

 

Similarly my original suggestion would replace the platform Starting signal with a bracket broadly similar in format to Signal B as drawn on your sketch - it would be correct for an earlier installation but you might feel that it would overpower the scene hence you could leave F as you have drawn it.  Similarly you could use a semaphore instead of a ground disc (or possibly use an elevated ground disc, I have a photo of a Southern one on a nice lattice post) as Signal E.  In your modelled era it would be most likely that discs would have replaced semaphores had there been semaphores at an earlier period but some old signals lasted a very long time with plenty of Pre-Group survivors around in the 1960s.

 

Linked below is a picture of a rather poor, fairly modern, lash-up of a slotted joint although in this case it doesn't have an FPL and the spring box which has been used is very definitely not the way the Western used to do the job (and neither is some of the rodding)

 

http://photos.swindonpanel.org.uk/picture.php?/1141

 

 

Mike would you mind clarifying something it the splitting signal is located at the turnout for the loop as we both suggested would you still need the disc signal?

 

Don 

 

I think not Don - you certainly could get away without it in a GWR/WR example (but this isn't GWR of course) and effectively at Bodmin North it could seemingly read to either line (unless the locking says otherwise).

[Donw]

Ah I was going to suggest that signal B should be moved to where D was and be replaced by the arm of the one at D. However Eric has thrown a spanner in the works. I can follow his reasoning but it seems to me that because there is a difference between the real and your layout  in that the loop extends out to the catch point and the outer home, the situation is not quite the same. I would suggest that provided the distance between the position of D and the catch point is comfortably longer than any train allowed onto the branch the situation on the model layout shouldn't arise. A shunt move would not pass the Advanced starter suggested by Mike and hence not cross the catch point. Should either the outer home or the advance starter be pulled off I assume the catch point lever would be pulled first to release the interlocking.  So I cannot see a need for any train to be stopped over the catch point. 

 I am assuming that should a train wish to depart from the loop signal C would act as the starter for that move. Presumably on the model the space available between the loop turnout and the bridge would be rather limited.

Eric and Mike are of course much more knowledgeable about real signalling. I am adding my comments from a viewpoint of what makes sense on a model where the distances are very compressed. For example considering the Wenford line, often in a model the turnout is right at the end of the platform with no room for a ground signal so it might be easier to fit a small arm or a disc mounted on the starter post (did the LSWR go for such things?) on the platform.

It may be thought on a model thinking about the signals beyond the bridge is irrelevant whereas in my view the levers should be on the frame and could activate some type of signal (LED on the panel?) as throwing either lever will inform the fiddle yard operator that you are ready for certain moves. Yes you  could use block bells but it sounds a bit odd when the FY and the station are so close, normally at a station you are only hearing half the bell conversation.

 

 

edit I see Mike has mentioned putting a disc on a nice lattice post while I was typing  which sounds nice

Edited February 16, 2017 by Donw

[N15class]

Guys this is all very interesting and will help me a lot if it ever Bodmin comes to fruition.i know nothing of signaling matters. I presume the ground ones are for letting the driver know he can go ahead no matter whether it is straight or to either side. I ask because although Bodmin is a small station it is festooned with them.

Sorry for the divergence Chris. The layout is coming along nicely.

Edited February 16, 2017 by N15class

[TheSignalEngineer]

OK, i've not altered the signal types yet but have moved those right of the bridge to be the correct side of the catch. FPLs have been added as discussed. This is where i'm up to: 

 

ScreenHunter_430 Feb. 16 20.21.jpg

 

I've also added some numbers (for trackwork) and letters (for signalling) to aid further description. 

 

Could I ask Eric, Don and Mike to confirm which signals need altering / moving using these references please??

 

Continued thanks all. 

Looking back at the trackwork pictures I can't see the need for trap point 4. Given the restricted space I would expect HP 3 to be box worked and possibly an extra ground signal in the clay siding. There wasn't one in the gas works siding either in LSWR or SR days but your Wenford line was only a shunt neck in the prototype so it probably wasn't necessary depending on the local working instructions.

[The Stationmaster]

Ah I was going to suggest that signal B should be moved to where D was and be replaced by the arm of the one at D. However Eric has thrown a spanner in the works. I can follow his reasoning but it seems to me that because there is a difference between the real and your layout  in that the loop extends out to the catch point and the outer home, the situation is not quite the same. I would suggest that provided the distance between the position of D and the catch point is comfortably longer than any train allowed onto the branch the situation on the model layout shouldn't arise. A shunt move would not pass the Advanced starter suggested by Mike and hence not cross the catch point. Should either the outer home or the advance starter be pulled off I assume the catch point lever would be pulled first to release the interlocking.  So I cannot see a need for any train to be stopped over the catch point. 

 I am assuming that should a train wish to depart from the loop signal C would act as the starter for that move. Presumably on the model the space available between the loop turnout and the bridge would be rather limited.

Eric and Mike are of course much more knowledgeable about real signalling. I am adding my comments from a viewpoint of what makes sense on a model where the distances are very compressed. For example considering the Wenford line, often in a model the turnout is right at the end of the platform with no room for a ground signal so it might be easier to fit a small arm or a disc mounted on the starter post (did the LSWR go for such things?) on the platform.

It may be thought on a model thinking about the signals beyond the bridge is irrelevant whereas in my view the levers should be on the frame and could activate some type of signal (LED on the panel?) as throwing either lever will inform the fiddle yard operator that you are ready for certain moves. Yes you  could use block bells but it sounds a bit odd when the FY and the station are so close, normally at a station you are only hearing half the bell conversation.

 

 

edit I see Mike has mentioned putting a disc on a nice lattice post while I was typing  which sounds nice

 

The whole point of having a slotted joint is to provide a catch point for trains running in one direction (usually due to the gradient in advance of of it but sometimes used for other reasons) but obviously in a single line it has to be closed and bolted for a train going in the other direction - hence the slotting by means of a lever in the signalbox and a the need for an FPL.

 

But when it is working as a catch point (i.e. for an arriving train) it poses the risk that SE highlighted in that an arriving train trails through it but after halting at the next signal in advance might either have vehicles running back as the couplings slacken or might even inadvertently setback a little.  This was in fact a common source of derailments where catch points existed approaching stations and had been provided to catch runaways but if a train 'slacked out' while standing at the signal in advance a vehicle could run back and be derailed.  Great if it was the last vehicle and it would probably rerail as the train drew forward if it hadn't run too far and one pair of wheels hadn't derailed but definitely trouble if it was an intermediate vehicle and especially if all wheels had derailed.

 

In the Bodmin North situation the catch point is left to spring over for an arriving train so the slot lever is not interlocked with the Home Signals - that's not needed.  But the slot lever would be interlocked with the Advanced Starter as clearing that signal requires the slotted joint to be closed (and bolted).

 

By strange coincidence there have been numerous examples of slotted joints at signalboxes which existed in your part of the world.  On the Taunton - Barnstaple line there was one at Milverton, one at Wiveliscombe, one at Venn Cross, two at Morebath Station, one at Morebath Jcn, one at Dulverton, another at East Anstey, one at Bishops Nympton,  and two at South Molton (one of which had an FPL).  On the West Somerset line 'in the old days' there was one at Bishops Lydeard, one at Crowcombe, one at Kentsford, and one at Williton.  All have gone and they are no longer needed on the West Somerset.

[TheSignalEngineer]

Regarding disc signals on the Southern, at times they did tend to go against convention and put them to the left of the post rather than to the side where the turnout was heading.

 

If you want one with an elevated disc there's a modern one at Swanage.

https://flic.kr/p/9Q4EBL

Edited February 17, 2017 by TheSignalEngineer

[2ManySpams]

Mmm, a big dose of reality bites this evening proving once again that my large (in a domestic environment) layout is actually pretty small when compared to the Bodmin North prototype inspiration. Grain store to bridge is only 2/5ths of what it should be. Rather naively I thought this wouldn't have too much effect on the signalling plan.

 

Wrong!

 

He's the mock up again (the real layout scenic section is 4m x 1m):

 

And the right hand end of the layout, with pretend bridge added:

[2ManySpams]

So the problems...

 

My flight of fancy signalling plan had two signals C and D in between the mainline and the rear siding:

 

Looking at my one signalling book, the offset between the rail and signal post should be 5'1" mind (a smidge over 35mm):

 

That means I'd need over 70mm (plus post width) between adjacent rails. Sadly I've only got 50mm, nowhere near enough:

 

There's certainly not the room to introduce more separation between tracks.

[2ManySpams]

Next problem is the major length reduction... brought home when you add a coach to the scene:

 

 

This shows that there's not even a coach length between the turnout blades at the end if the loop and the bridge. Just about every shunting move involving the loop will therefore involve going beyond the bridge. Even just a loco running around...

 

[2ManySpams]

Going back to a little visualisation using the mock up...

 

Here's where trains waiting to leave would be sitting.

 

The Ivatt tank and coaches represent the starting position for a train in the platform road heading for either the mainline or the (freight only) Wenford branch. The N Class and wagons represent the starting position of a goods train heading off down the mainline.

 

I'm assuming that one signal can't cope with all these situations??

 

So, is the solution something like this?:

 

A starter at the platform end to signal departures from the platform road to either the mainline or Wenford branch, plus one on the wrong side of the mainline next to the bridge for the loop line departures?

 

Is the second one necessary, or do folk have alternative ideas?

[2ManySpams]

My thoughts regarding the original signal proposed at D are that perhaps a ground signal would be appropriate but that the main approach signal would be on the opposite side of the bridge further downhill. Am I barking up the wrong tree??

 

Reality makes my head hurt.

[TheSignalEngineer]

As in the prototype. Bodmin North had this arrangement if you look at the points closest to the platform. As you have taken out the points nearest to the bridge just replace signal D as shown by a ground signal and put signal C and the inner home (was D) on the other side of the bridge. Solves the clearance problems as well.

 

Eric

[TheSignalEngineer]

Thinking a bit more about it, signal D could remain as originally shown but in reality sighting would be abysmal and that would probably be avoided. Also with the one lot of boints being omitted a main signal at that location would not serve much purpose as the distances have been reduced as well.

 

That means I am now thinking probably a ground signal at D and signal C on the other side of the bridge.

 

Eric

[Mark Forrest]

There's certainly not the room to introduce more separation between tracks.

I have a similar scenario from Bloxwich that I aim to (eventually) include on Fryers. There the signal before the level crossing (from the Walsall direction) had a post outside the siding with a bracket to place the signal in the right place; I'll find a photo.

[2ManySpams]

Thinking a bit more about it, signal D could remain as originally shown but in reality sighting would be abysmal and that would probably be avoided. Also with the one lot of boints being omitted a main signal at that location would not serve much purpose as the distances have been reduced as well.

 

That means I am now thinking probably a ground signal at D and signal C on the other side of the bridge.

 

Eric

 

Something like this Eric?:

 

[TheSignalEngineer]

That's what I was thinking as the minimum amount of signalling. 

 

I still think trap 4 is superfluous and HP 3 should be box worked. There isn't room to get signal E on the left of the line between points 3 and 4 so if the trap is retained it would have to go to the right of the line, but then there may be a conflict with signal D.