1960's ex GWR Yard - Catch points and signalling advice please...

[dpaws]

Sorry Guys, I see that this is a recurring topic! 

 

First of all, the Templot track-plan without catch trap points, 1960, BR (W), along a sunny branch-line to somewhere...

 

 

And a corresponding schematic for illustration, with my guess at where catch trap points should be. I've identified the only through traffic route in green, so I've considered this to be the primary route, protected from all other exits.

 

You'll note on the Templot that there's a small (off-scene) sector plate, but on the schematic there's a single slip shown, with a stub siding (g). That is only to illustrate what the sector plate reproduces off-scene, in my head, in the world beyond.... 

 

The platform end shown I've assumed to be a #3, where branchline mixed train services terminate. A platform 1 & 2 somewhere else further off-scene would serve the through branch traffic.

 

Beyond scenic exit (d) there's a line out to a quarry past a level crossing. The only through traffic (green route) would be mineral wagons. There's none running today because the level crossing is closed due to an accident...

 

(a) & (b) are local goods sidings, with buffer stops.

 

© is a headshunt serving exit (e), with a buffer stop.

 

(d) is a stage exit - a mineral line leading to a level crossing and a quarry

 

(e) is a stage exit - leading to a small coaling stage and a creamery, both off-stage

 

(f) is a stage exit, it represents the first sector plate position and leads to the middle line / platform loop off-stage

 

(g) is off-stage, a theoretical bay siding and the lower second sector plate position

 

(h) is Platform #3 receiving mixed train formations

 

So, if you'd all be kind enough to hold my hand through this....

 

Question (1) Catch Trap points - please, where should they really be located? 

Edited July 5, 2017 by dpaws

[imt]

I not sure whether this is the right thread for this - maybe http://www.rmweb.co.uk/community/index.php?/forum/35-permanent-way-signalling-infrastructure/ would be better as I am not sure how many of the engineers watch this one.  Here's a quick starter for 10.

 

Firstly they ain't catch points - I think you mean traps.  Catches catch run away stock at the bottom of slopes.

 

Secondly the purpose of a trap is to protect passenger movements from run away goods stock - forgot to put the brakes on? - or movements which might clash with passenger traffic.  So many of your suggestions might be less than necessary.

 

Proper answers from the experts might require some explanation of HOW this layout is intended to operate.  Is platform 3 a dead end.  Why do you need a l/h point off the passenger line d-h to g?  The line from g (which crosses the main line)  would need to have a trap to protect the main line.  I don't think you need a trap from the platform onto the main line near d or at the end of the platform. Since the line c-e goes nowhere near the main/passenger line then no trap is needed.  IF d-f is a main (passenger) line then the traps a-f and b-f are needed.  Possibly not if this is a goods only line?

 

So the experts out there will help - but give a bit more detail to help them first.

Edited July 5, 2017 by imt

[dpaws]

I not sure whether this is the right thread for this - maybe http://www.rmweb.co.uk/community/index.php?/forum/35-permanent-way-signalling-infrastructure/ would be better as I am not sure how many of the engineers watch this one.  Here's a quick starter for 10.

 

Firstly they ain't catch points - I think you mean traps.  Catches catch run away stock at the bottom of slopes.

 

Secondly the purpose of a trap is to protect passenger movements from run away goods stock - forgot to put the brakes on? - or movements which might clash with passenger traffic.  So many of your suggestions might be less than necessary.

 

Proper answers from the experts might require some explanation of HOW this layout is intended to operate.  

 

Is platform 3 a dead end. To the west there's only a mineral line, to the east joins it the branch-line, from where the trains arrive.

 

Why do you need a l/h point off the passenger line d-h to g?  To serve (g), but I feel that you haven't compared the two diagrams - (g) and it's theoretical trap don't exist, but it creates the reason for me to shunt say a horse box van from the platform to the bay siding (g), after which the hand of God comes into play... 

 

I don't think you need a trap from the platform onto the main line near d or at the end of the platform. Platform end maybe not, as (g) should be trapped, but close to (d) for me yes, to protect the through goods route?

 

Since the line c-e goes nowhere near the main/passenger line then no trap is needed.  Ahhh, I was protecting the crossing as there's a restricted view on the approach

 

IF d-f is a main (passenger) line then the traps a-f and b-f are needed.  Possibly not if this is a goods only line? No, quarry only, but as a through traffic route shouldn't that be protected?

 

So the experts out there will help - but give a bit more detail to help them first.

 

You're perfectly correct, traps, my bad. I'm learning, slowly...

[imt]

You're perfectly correct, traps, my bad. I'm learning, slowly...

 

"I don't think you need a trap from the platform onto the main line near d or at the end of the platform. Platform end maybe not, as (g) should be trapped, but close to (d) for me yes, to protect the through goods route?"

 

I think this is where I should bow out - I am not an expert in these matters, just someone who has read the experts on here.  HOWEVER in my (non-expert) opinion, IF the line is mineral only except for passenger trains to platform 3, then the ONLY traps you need are to protect the passenger line and those would be on d-f just before the point to platform 3 and on g near the crossover/slip or whatever on f.  The rest would be under the control of shunters or maybe even private.

[The Stationmaster]

II'll carry on here if you don't mind (perhaps lock the other thread you've started or 'hide' the post otherwise we could get in a tangle).

 

The layout definitely comes across as rather 'busy' but he key point (sorry) is that there is only the one passenger line (h) and the passenger trains arrive from and depart towards the east.  So it is the only line that needs any sort of trap protection - everything else is effectively a siding or, in the case of (d) a Goods Line.   Therefore a passenger train terminating/reversing at the platform has to be protected from errant movements of engines or vehicles - simple as that.  And that protection can be achieved without using any trap points at all as the turnout from line h to line g would lie normal towards g thereby immediately diverting any errant movement from the west away from the platform line and towards line g.

 

I am going to assume there are no long or steep gradients because if there were we might also need to think about the connection from line h into line f but in any case if signalbox worked it would lie normal for the route shown in green thus providing a second trap and useful for errant moves from the quarry.

 

There would need to be a stop signal at the end of the platform to protect the point (i.e. to stop passenger trains/running round engines from running through it and i would assume a ground signal reading through it once set for an engine to run round although it might even be a slotted joint (i.e. it is sprung to lie in a particular direction and the running round engine would simply trail through it.  But we're now leaping a bit ahead of the original question and the very simple answer to it.

[martin_wynne]

Firstly they ain't catch points

 

They are to a permanent-way engineer. "Trap" describes the function, not the physical object. Traps can also be full turnouts, slips, sand drags, etc.

 

So in this case they are catch points acting as traps. Templot is about track, not operations, so in Templot they are "catch points" as shown on the full-size manufacturing drawings.

 

regards,

 

Martin.

Edited July 5, 2017 by martin_wynne

[dpaws]

The layout definitely comes across as rather 'busy' but he key point (sorry) is that there is only the one passenger line (h) and the passenger trains arrive from and depart towards the east.  So it is the only line that needs any sort of trap protection - everything else is effectively a siding or, in the case of (d) a Goods Line.   Therefore a passenger train terminating/reversing at the platform has to be protected from errant movements of engines or vehicles - simple as that.  And that protection can be achieved without using any trap points at all as the turnout from line h to line g would lie normal towards g thereby immediately diverting any errant movement from the west away from the platform line and towards line g.

 

I am going to assume there are no long or steep gradients because if there were we might also need to think about the connection from line h into line f but in any case if signalbox worked it would lie normal for the route shown in green thus providing a second trap and useful for errant moves from the quarry.

 

There would need to be a stop signal at the end of the platform to protect the point (i.e. to stop passenger trains/running round engines from running through it and i would assume a ground signal reading through it once set for an engine to run round although it might even be a slotted joint (i.e. it is sprung to lie in a particular direction and the running round engine would simply trail through it.  But we're now leaping a bit ahead of the original question and the very simple answer to it.

 

Many thanks indeed Mike, and I even understood all of that!

 

I think I've been immersed in risk assessments for too long and have become over-protective of everything - if it's only the passenger trains that need protection then that makes it a whole lot simpler! (You're perfectly correct in assuming that gradients are not present.) 

 

It is, as you implied, an over-indulgence in complex trackwork for such a cramped space - the same but spread over twice the length would be preferable, I concede. But I value turnout formations as artwork, and commissioned hand-made trackwork is somewhat of a selfish indulgence.... To be fair, once the buildings etc are in place and the view is restricted through the proscenium arch the impression is far more favourable than the over-head view suggests. Initial "peekaboo" shots with the camera lens are quite favourable, though not in Nevard's league for sure... not yet...

 

Now, you mentioned a signal box... which of the turnouts would be under the control of a signal box, and which would be controlled with local ground frames?

 

I assume the single slip tie bars would be linked to a ground-frame, the three-way and the turnout bottom left would be controlled by the signal box and the platform end turnout would be sprung (very neat!) with a ground-frame over-ride to permit a movement from the lower loop into the platform rather than the default routing to (g)?

 

Solely out of interest, if there was a passenger service (h) to (d) and beyond then... the stop signal and ground signal at the platform end would be replaced by a starter signal and a shunt ahead signal respectively, with a trap inserted on the green line before the bottom left hand turnout to protect the passenger line?

 

Thanks again, very much obliged 

[Stephen Freeman]

Many thanks indeed Mike, and I even understood all of that!

 

I think I've been immersed in risk assessments for too long and have become over-protective of everything - if it's only the passenger trains that need protection then that makes it a whole lot simpler! (You're perfectly correct in assuming that gradients are not present.) 

 

It is, as you implied, an over-indulgence in complex trackwork for such a cramped space - the same but spread over twice the length would be preferable, I concede. But I value turnout formations as artwork, and commissioned hand-made trackwork is somewhat of a selfish indulgence.... To be fair, once the buildings etc are in place and the view is restricted through the proscenium arch the impression is far more favourable than the over-head view suggests. Initial "peekaboo" shots with the camera lens are quite favourable, though not in Nevard's league for sure... not yet...

 

Now, you mentioned a signal box... which of the turnouts would be under the control of a signal box, and which would be controlled with local ground frames?

 

I assume the single slip tie bars would be linked to a ground-frame, the three-way and the turnout bottom left would be controlled by the signal box and the platform end turnout would be sprung (very neat!) with a ground-frame over-ride to permit a movement from the lower loop into the platform rather than the default routing to (g)?

 

Solely out of interest, if there was a passenger service (h) to (d) and beyond then... the stop signal and ground signal at the platform end would be replaced by a starter signal and a shunt ahead signal respectively, with a trap inserted on the green line before the bottom left hand turnout to protect the passenger line?

 

Thanks again, very much obliged 

Hi Steve,

 

I've replied separately to you with revised plan with just 2 catch(trap) points, which could be omitted if the other line g/f to d was not a passenger train route, if it was (and to my mind it would be logical that it could be), I think they would be needed  but forgot to mention a signal box. I think that this would be off-scene, as it would need to be where the rest of the station is supposed to be.

 

d - passenger - starter and shunt ahead.

d - goods only - stop signal and ground signal

You could have a Goods yard exit signal ( which line is the exit?) but that is optional as could be off-scene.

[The Stationmaster]

Many thanks indeed Mike, and I even understood all of that!

 

I think I've been immersed in risk assessments for too long and have become over-protective of everything - if it's only the passenger trains that need protection then that makes it a whole lot simpler! (You're perfectly correct in assuming that gradients are not present.) 

 

It is, as you implied, an over-indulgence in complex trackwork for such a cramped space - the same but spread over twice the length would be preferable, I concede. But I value turnout formations as artwork, and commissioned hand-made trackwork is somewhat of a selfish indulgence.... To be fair, once the buildings etc are in place and the view is restricted through the proscenium arch the impression is far more favourable than the over-head view suggests. Initial "peekaboo" shots with the camera lens are quite favourable, though not in Nevard's league for sure... not yet...

 

Now, you mentioned a signal box... which of the turnouts would be under the control of a signal box, and which would be controlled with local ground frames?

 

I assume the single slip tie bars would be linked to a ground-frame, the three-way and the turnout bottom left would be controlled by the signal box and the platform end turnout would be sprung (very neat!) with a ground-frame over-ride to permit a movement from the lower loop into the platform rather than the default routing to (g)?

 

Solely out of interest, if there was a passenger service (h) to (d) and beyond then... the stop signal and ground signal at the platform end would be replaced by a starter signal and a shunt ahead signal respectively, with a trap inserted on the green line before the bottom left hand turnout to protect the passenger line?

 

Thanks again, very much obliged 

 

All can be simplicity itself Steve as that 1960s date gives some leeway as it was the era of considerable rationalisation which sometimes included just the signalling and left the track alone - as would probably happen at a place like this.

 

We come back really to the situation where almost everything is a siding and even the quarry line would have inevitably have been worked under what we knew as Table C2 although it only gained that name during the 1960s but the method didn't really change from what was already established in numerous places).   Thus by the early 1960s I would only see that point operating as trap worked by the signalbox (which would be off-secene to the east) with the semaphore stop signal at the platform end fixed at danger (a rarity on the Western but something which gradually appeared in the '60s) and a ground disc - again worked by the signalbox - to authorise shunting movements past the stop signal  (exactly such arrangement existed at West Drayton after various rationalisations in the early 1960s).

 

All other points would be hand worked by immediately adjacent hand levers - by far the best and quickest arrangement for shunting.  The only likely alternative by the early '60s would be ground frames to control the connections to/from the 'green line' but I think that highly unlikely as even before the '60s as it would have been much simpler and cheaper to place the area under the control of a Shunter (or maybe a Yard Foreman?) who would also  'control' the line to the quarry and any movement to/on/from it would be at his say so.

 

This would involve minimal visible 'signalling' with no more that traditional GWR style STOP boards controlling the exit from the quarry line and, probably, also the entrance to it.  Similarly before clearing the ground disc at the platform end the Signalman would have to obtain permission from the Shunter to clear the signal - a wholly normal and widespread procedure.

 

That's the simple answer.  If - in a relatively confined area - you want to go in for signals there will be a virtual forest of them although most would be ground discs.  Effectively what would be unavoidable would be the 'green line' coming under the control of a signalbox with all points on it/leading to or across it worked by that signalbox.  The trapping arrangementswould be unaltered but for ease of working the signalbox would have to be at that end - shunting would take too long if messages had to be conveyed to/from a 'box a couple of hundred yards away - and it would be exactly the sort of signalbox that late 1950s, if not even earlier, economies would have done away with as it would have mainly been the Signalman pulling points for the Shunters rather than the Shunters pulling them for themselves.

[DCB]

It looks massively over complicated for the GWR.  Their final branch stations had 4 points only.   Have you built it yet?   If not run your finger along where shunting moves will take place.

The E - C headshunt arrangement is too short for anything meaningful and the G pointwork very over complicated if it faces a mineral branch not the west of england main line.

Most of the signals would be off stage, most of the trap points, maybe even a sand drag stage left off stage, the signal box would need to be the other end of the station for token purposes so quite how the sidings would be worked is debatable, ground frame released from box?

I was operating (trying to make it work electrically actually) a branch terminus at the weekend and the kick back sidings are just a pain. A shunt takes for ever and is soooooo boring.

Much better to forget kick backs and stick with simple and concentrate on getting the incoming wagons in the outgoing out and the part emptied/ loaded/ waiting for loads/ cripples spotted where required

[dpaws]

Wow! Thank you so much Mike, very informative - and I really appreciate your patience to explain the scene overall all at my level, the working practices and consequences of the incoming rationalisation - hats off to you. I do find it all so interesting; another world that sadly seems to have disappeared so rapidly.

 

Thanks too Stephen, the plan looks good - looking forward to everything

[dpaws]

It looks massively over complicated for the GWR.  Their final branch stations had 4 points only.   Have you built it yet?   If not run your finger along where shunting moves will take place.

The E - C headshunt arrangement is too short for anything meaningful and the G pointwork very over complicated if it faces a mineral branch not the west of england main line.

Most of the signals would be off stage, most of the trap points, maybe even a sand drag stage left off stage, the signal box would need to be the other end of the station for token purposes so quite how the sidings would be worked is debatable, ground frame released from box?

I was operating (trying to make it work electrically actually) a branch terminus at the weekend and the kick back sidings are just a pain. A shunt takes for ever and is soooooo boring.

Much better to forget kick backs and stick with simple and concentrate on getting the incoming wagons in the outgoing out and the part emptied/ loaded/ waiting for loads/ cripples spotted where required

 

Thanks for your comments David, though I feel you haven't understood - G doesn't exist, it's a Faller sector plate. E-C accommodates the 2-6-2 that I want it to, or a Pug with a couple of milk tankers... Nothing more is needed, goods traffic is sourced from mixed traffic formations only (ignoring the hypothetical mineral through goods traffic....). 

 

The challenge is a self-contained 4'x1' cameo that (eventually) will be a centerpiece on our canal boat where I hope friends will enjoy the cameo as 3D art as much as they will enjoy the Inglenook type shunting challenges - it's an 0-6-0 and one wagon at a time sorta scene, slowly slowly and in minimum space, just like all things on the canal!

[TheSignalEngineer]

They are to a permanent-way engineer. "Trap" describes the function, not the physical object. Traps can also be full turnouts, slips, sand drags, etc.

 

So in this case they are catch points acting as traps. Templot is about track, not operations, so in Templot they are "catch points" as shown on the full-size manufacturing drawings.

 

regards,

 

Martin.

 

Arguments about what these are called have gone on long into the night on many occasions.

 

(Puts on Pedant hat)

 

Looking at the terminology as used by those writing the rules, the first reference I have is the 'Requirements, Etc of the Board of Trade in regard to the Opening Of Railways' . This was published in 1885.  It refers to the provision of 'Safety Points' to protect running lines from movements within sidings and the provision of 'Catch Sidings' or 'Throw Off Switches' to stop runaways on gradients.

These are the relevant sections from the 1892 reprint marked up with the proposed 1902 revision.

 

Sidings

 

Gradients

 

I don't have an electronic copy of the 1925 revision but it is substantially the same with the exception that it doesn't use the wording 'Catch Siding'

 

The 1950 Requirements had progressed to this.

 

Sidings

 

Gradients

 

Here the words Trap Points and Catch Points are used in the way that most railway people now understand them.

 

(Changes Pedant Hat for Tin Helmet and Exits Stage Left)

Edited July 6, 2017 by TheSignalEngineer

[imt]

Thank you so much for all of that.  As you say I expect others will argue with it, but it does help the ignorant like me understand better!

[martin_wynne]

 

Arguments about what these are called have gone on long into the night on many occasions.

 

... (snipped)

 

Yes, but all that is referring to the operating function of the said points. It makes no mention of what the physical objects are called, just refers to them as "points".

 

In Edition 3 (1964) of the PWI Handbook "British Railway Track - Design, Construction, Maintenance" they are referred to as Catch Points throughout, regardless of the operating purpose for which they are used. Page 154 discusses the types of Catch Points used for different types of "Catch Roads".

 

In Edition 4 (1971), all the references have been changed to "Trap Points".

 

Edition 3 was the last to contain significant details of bullhead track, and many sections are clearly carried over from earlier days. Edition 4 was largely re-written for modern flat-bottom practice, and contains little reference to bullhead.

 

So you could argue that if these things are bullhead, they are catch points. If they are flat-bottom they are trap points.

 

The GWR drawings for them are clearly labelled "Catch Points" of various designs -- there is a whole chapter about them in David Smith's book on GWR track.

 

regards,

 

Martin.

[TheSignalEngineer]

I have the 1950 edition of the PWI book at home. I will check later how they are referred to in that one.

Edited July 6, 2017 by TheSignalEngineer

[dpaws]

So you could argue that if these things are bullhead, they are catch points. If they are flat-bottom they are trap points.

 

I do like your way of thinking... 

[Grovenor]

 

Yes, but all that is referring to the operating function of the said points.

Quite, but it is the operating function that is the subject of this topic, the designation given to the hardware by P-Way engineers is irrelevant.

Regards

Even though 'Safety points', 'Trap Points', 'Catch Points and 'Derails' if across the pond are all essentially for the same purpose, preventing a possible big accident by creating a certain small one.

Edited July 6, 2017 by Grovenor

[martin_wynne]

Quite, but it is the operating function that is the subject of this topic, the designation given to the hardware by P-Way engineers is irrelevant.

 

Well yes and no. This topic could use either term, depending on the OP's intent. He referred to the GWR in the topic title. And on the GWR they were always catch points.

 

The first line of the topic refers to inserting them in a Templot track plan. Templot is about track, and also calls them catch points.

 

But my reason for replying in detail was that as always when anyone mentions catch points on RMweb, someone pops up to say that they aren't catch points.

 

Martin.

[Grovenor]

Actually my experience is that, whenever there is a discussion involving trap points, you pop up to insist that P-way call them catch points. I have not noticed the SM calling traps catch points, GWR or not. The Op was asking where to put them which is an operating/signalling issue not a P-way issue.

Regards

[dpaws]

Actually my experience is that, whenever there is a discussion involving trap points, you pop up to insist that P-way call them catch points. I have not noticed the SM calling traps catch points, GWR or not. The Op was asking where to put them which is an operating/signalling issue not a P-way issue.

Regards

 

 A constructive contribution to the thread would be most welcome...

Edited July 6, 2017 by dpaws

[Grovenor]

A constructive contribution to the thread would be most welcome...

Appropriate answers were given in posts #2,#4, #5, no need to repeat that info.

regards

[81C]

You just can't make this sort idle banter up.         

[TheSignalEngineer]

Appropriate answers were given in posts #2,#4, #5, no need to repeat that info.

regards

That's why I rarely follow question threads for more than one or two pages.

[The Stationmaster]

 A constructive contribution to the thread would be most welcome...

 

I'll just pop in a couple of items from the GWR 1933 Rule Book.

 

Rule 62 read as follows, in its entirety :-

 

'Trap points, derailers, and scotch blocks must be set to secure safety, and, except when movements are required to be made over the line on which they are provided, they must be kept in position to prevent any vehicles escaping onto running lines.'

 

Rule 63 read as follows, in its entirety :

 

'Runaway catch points worked from signal boxes must be kept normally open in order to prevent any vehicle running back.  When it is necessary for a movement to be made over runaway catch points in the facing direction, whether they are worked from a signal box or not, care must be taken that the points are properly set and secured for the movement.'

 

Rule 111, Clause a, Sub Clause iii read - in the relevant part;

 

[Guards or Shunters etc   ...   must satisfy themselves that -]

 

'After [shunting] operations are completed trains or vehicles are left clear of any running lines and within trap points, derailers, or scotch blocks   ...' 

 

To me these Rules alone make pretty clear the distinction between trap points and catch points and make very clear the principle of both.  

 

To confuse the two is in my view as a professional railwayman not exactly the best thing to do particularly when we are talking about matters relating to safety where clarity of understanding is required.  I can understand the layman falling prey to such confusion especially as some railwaymen in the past were themselves guilty of misusing the terminology but it has long been absolutely clear to alll who care to the read the Rule Books or be examined in their knowledge of them (and of course many on the railway were required to have knowledge of Rules & Regulations if they were involved in the working of the railway).