Simple crossover point operation - which sequence?

[Stubby47]

For a simple single main line, with a siding and kick-back siding, in which order were the two points manually operated?

 

Assuming they were not operated together, I would think that to set the route for the siding, the kick-back point would be set for the crossover 1st, followed by the main.

And to set the route for the main, the main point would be set first, followed by the kick-back.

 

This would give the most protection to a train on the main.

 

But is that correct?

 

TIA

Stu

[CloggyDog]

Morning Stu. 

 

I think it's much more likely they be operated as a pair, together simultaneously off one lever in the box as that guarantees protection. 

 

If they are operated separately, then as you describe. 

[Stubby47]

I did wonder if that would be the case, especially from a box, but would it be also true from a ground frame?

[MikeB]

There may be differences depending on era and location, but a few signal box diagrams that I've just looked at suggest that the points would operate as a pair, even if controlled by a ground frame..

[Michael Hodgson]

The normal arrangement would be to treat it as a crossover worked by a single lever.  That's the most economical way of doing it, and it the safest, makes no difference whether that's in a box or GF.  If it's in a GF, the GF itself would be locked by the signal box, so would require a release before you could set the points for the siding.  This could be electrical or mechanical.  Or an equivalent protection would be to use an Annetts key, which might be attached to a single line staff or could be issued by the signal box, and would lock conflicting movements until the key is returned which is only possible with the GF locked with all its levers normal.

 

You might well need a second lever working a facing point lock (on the main line for trains coming from the left) however.  If the points were power worked, there would still be only one lever as the FPL is built into the mechanism. 

 

The siding trap is required to protect the main line from any rogue movements from the siding, so it should not be operated first.

 

There are a few rare circumstances in which you might want to be able to work the points separately,  but this is dependent on what other hazards exist in the area.  The most obvious is where the line is steeply descending from left to right, and you need the main line point to lie normally towards the siding as a safeguard against runaways to protect something to the right of the layout shown. 

[Stubby47]

THanks all for your input.

 

The question is raised as I want to physically operate the two points independently, although 'together', using servos and a delay function (so one point is changed first, followed by the second).

 

Whilst this would seem to be against normal practice, Rule 1 applies,  but I still want the operation to at least seem organised.

 

Although the left point and lower central point are some distance apart, they do form a 'crossover', and there is potential for wagons to be stood on the central point whilst the left point is changed.

 

This would mean that the crossover is not always operated as such, but has the option.

[Happy Hippo]

I am assuming that this set up is from a running line to a set of sidings.

 

If you want to operate the turnouts independently then I'd suggest you need an additional trap point  between the two  that seem to be causing the issue.

 

If you look at Milverton:

 

 

You can see the facing point,complete with fpl operating in conjunction with a trap.

 

The lever for the line into the goods shed is hand operated.  Once the road is set for the goods headshunt any traffic coming into the yard could trail through the lever operated point if required.

 

If the yard point was set for the 'main' and the point and trap were set for main running, then the ptrap would protect the main which is what it is supposed to do 

 

The size and complexity of the track diagram is of no consequence it is only the function of the release from the main to the siding and it's safe operation that is of importance.

 

Likewise, if you look at North's Collieries in S Wales, you'll see there is a 'standard' crossover arrangement where one lever operates both turnouts; there is no requirement for an fpl as the line is freight only.

 

But both points operate as a single unit and they are also further protected by the bracket signal or independent disc.

 

 

From my understanding of signalling, it would be one of either arrangements as illustrated above.

 

(Thanks to the Signalling Record Society website for the  diagrams.)

 

 

 

[Jeremy Cumberland]

8 hours ago, Stubby47 said:

there is potential for wagons to be stood on the central point whilst the left point is changed.

Why would you want to change the points at all, if there is nowhere for a train to go?

 

You should say which, if any, lines are used by passenger trains. Passenger lines need to be protected from non-passenger lines by trap points or crossovers, almost always co-acting, but in most situations non-passenger lines don't need protecting from other non-passenger lines, nor do passenger lines need protecting from other passenger lines. If the bottom line is a passenger line and the top lines aren't, and you want to move the bottom left point independently of the middle point, then you need a trap point (worked off the same lever as the bottom left point), as Happy Hippo says.

 

Are the middle points all hand worked (as in the Milverton diagram above)? This is the only arrangement I can think of when you might want to work the points independently. Even so, I can't think why the signaller would set the bottom left point for the middle sidings if the line was blocked (which presumably the signaller would be able to see), even if the signaller had no control over the middle points. With hand worked points, there is no sequence at all; hand worked points can be set either way at any time the person operating the point wishes, and it need not be set at all for a train entering the sidings from the main line, but could simply be trailed through (this doesn't tend to work very well in a model). But I would still not expect the main line points to be set for the sidings unless (for an incoming train) there was somewhere for the train to go, or (for an outgoing train) the train was formed up and ready to depart.

 

However, there are all sorts of oddities on the prototype, and Coombe Junction on the GWR Looe branch has an unusual arrangement with what looks to be a crossover having separate levers. Here is a link to the diagram: https://signalbox.org/~SBdiagram.php/?id= 372. Levers 15 and 16 set the route for either Liskeard (15 normal, 16 reverse) or Looe (15 reverse, 16 normal). With both points normal, neither route is set. I am not sure why this arrangement was decided upon, but there is a very steep gradient down from Liskeard, so 16 normal provides protection from runaways. For trains to or from Liskeard, points 15 must be set first, before points 16 are set, and 16 must be returned normal, for the siding, before 15 can be set for the Looe line. Both lines are passenger lines so if it weren't for the gradient, there would be no need for 16 at all (although I think it did use to serve a local industry, when it would have needed a trap point on the siding).

[DCB]

The problem as I see it is the main line point would be operated from the signal box or ground frame, through (Inter) Locking so the Trap could only be set toward the main line when the main line point was set towards the trap and the main line point could not be reset to straight before the the trap point was set to the trap.   The Main line point and is FPL had to be set before any signals post or ground could be pulled off.

The other points would be operated by levers beside the track,   Two completely different modes of operation, the signal box/ GF can be represented accurately but not as per 2024 the hand lever though I expect fully working OO scale automorons to be available soon 

[Nick C]

22 hours ago, Stubby47 said:

THanks all for your input.

 

The question is raised as I want to physically operate the two points independently, although 'together', using servos and a delay function (so one point is changed first, followed by the second).

 

Whilst this would seem to be against normal practice, Rule 1 applies,  but I still want the operation to at least seem organised.

 

Although the left point and lower central point are some distance apart, they do form a 'crossover', and there is potential for wagons to be stood on the central point whilst the left point is changed.

 

This would mean that the crossover is not always operated as such, but has the option.

From what I understand from your other thread, this is entirely inside a yard - in which case all of the points would be hand-worked under the control of the shunter. Therefore I'd say that the order would depend on where the shunter was to start with - he'd work the closer end first then walk to the other one!

[DCB]

At the end of the day it's impossible to make models of these cramped  locations work prototypically.  They wouldn't have existed.    Locos didn't constantly run round 3/4/5 wagon rakes.  If the engine the wrong end then a fly shunt,?   get the wagons rolling by pulling them, shunter walks / runs alongside, uncouples the loco, loco accelerates and enters a siding and the shunter outruns the stock and changes the points or the fireman or a second shunter changes the points as the stock rolls past at walking speed. Even an empty wagon has a fair bit of momentum. 

Its a very quick operation to change manual points with a lever beside them, a lot quicker than a Tortoise motor can do it so you don't need much separation between loco and stock.  It can't really be done with a GF or Signal Box as the pulls are a lot harder and the signal man would not be able to see what was going on.

Few sidings had their points operated by the signal box. mainly small stations where no one was employed as a shunter.  For one thing engines whistling up to wake the signalman when they wanted points changed would annoy the local squire who went to Eaten with some of the directors and he would give said directors a damned good wigging when they next met. or worse still would write to the Times and complain

[Stubby47]

6 hours ago, Nick C said:

From what I understand from your other thread, this is entirely inside a yard - in which case all of the points would be hand-worked under the control of the shunter. Therefore I'd say that the order would depend on where the shunter was to start with - he'd work the closer end first then walk to the other one!

 

Yes, it is all inside a freight-only yard (although the prototype does have a passenger platform under the gateway to HMS Drake, which if I have room I might replicate).

 

And yes, all hand operated points would save on point-rodding, and does then allow points to be moved independently and in any order.

[Stubby47]

On 11/08/2024 at 12:29, Happy Hippo said:

If you want to operate the turnouts independently then I'd suggest you need an additional trap point  between the two  that seem to be causing the issue.

 

I understand the need for a trap point, however this is all freight ( except see above post), and hopefully all flat with an imagined rising gradient out of the yard.

 

This is, in essence,  an inglenook shunting puzzle, albeit with a loop and extra kick-back siding.

So 'real' operations are probably not followed, however I want the crossover operations to at least look something like realistic.

 

Thanks again for all your input. 

[kevinlms]

On 11/08/2024 at 21:07, Stubby47 said:

THanks all for your input.

 

The question is raised as I want to physically operate the two points independently, although 'together', using servos and a delay function (so one point is changed first, followed by the second).

 

Whilst this would seem to be against normal practice, Rule 1 applies,  but I still want the operation to at least seem organised.

 

Although the left point and lower central point are some distance apart, they do form a 'crossover', and there is potential for wagons to be stood on the central point whilst the left point is changed.

 

This would mean that the crossover is not always operated as such, but has the option.

Given that the diagram looks like a transporter wagon might be used for standard/narrow gauge operation, does it matter which point operates first, as one in NG and the other is SG? Or even BG/SG!

 

Am I the only one thinking outside the box?

[Wheatley]

Whatever.

Edited August 13 by Wheatley

[Edwin_m]

12 hours ago, Stubby47 said:

Yes, it is all inside a freight-only yard (although the prototype does have a passenger platform under the gateway to HMS Drake, which if I have room I might replicate).

If you do that you may need a trap between the yard and the platform, so anything rolling out of the yard when not authorised to do so would not come into contact with a passenger train.  Depending on signalling arrangement this trap might need a signal, or be controlled by a ground frame unlocked by possession of the token or some other means.  

[kevinlms]

7 hours ago, Wheatley said:

No. If its freight only then there in most cases* there isn't really a need for anything to be trapped. 

 

If they're hand points then whichever one the shunter reaches first gets operated first. 

 

*There may be some local feature which makes it desireable for the siding to be trapped, eg a  gradient and something important and/or expensive to protect, but I can't think of an example. But hand points are easy to forget so in those circumstances you're back to points worked together, rodding and ground frames etc.  

 

The general requirement to trap sidings was to protect passenger lines. 

Perhaps you've missed that I was suggesting based on OP's track plan, that it looks like 2 gauges, due to the different thickness on the lines used?

 

But never mind.

[Stubby47]

1 hour ago, kevinlms said:

... based on OP's track plan, that it looks like 2 gauges, due to the different thickness on the lines used?

Yes, it's OO & OO9.

 

 

 

 

 

[Nick C]

2 hours ago, kevinlms said:

Perhaps you've missed that I was suggesting based on OP's track plan, that it looks like 2 gauges, due to the different thickness on the lines used?

 

But never mind.

I thought Stu was referring to the middle point and the top-left one on his plan as the crossover?

 

 

[Stubby47]

14 minutes ago, Nick C said:

I thought Stu was referring to the middle point and the top-left one on his plan as the crossover?

 

 

 

Correct, I was.

Crossover might be a loose term, seeing as how the points are some distance apart, but the original question could also apply to the two other points, which do appear to be a crossover ( although not actually laid yet, so could also be separated).

 

I think, given all of the above info, I can operate the points one at a time, as if they were yard points with levers, which, I think, will look more interesting. 

 

I probably also need to add a trap point between the main point and the kickback to the transfer siding point, but this might just be dummy one.

[Jeremy Cumberland]

27 minutes ago, Stubby47 said:

 

Correct, I was.

Crossover might be a loose term, seeing as how the points are some distance apart, but the original question could also apply to the two other points, which do appear to be a crossover ( although not actually laid yet, so could also be separated).

 

I think, given all of the above info, I can operate the points one at a time, as if they were yard points with levers, which, I think, will look more interesting. 

 

I probably also need to add a trap point between the main point and the kickback to the transfer siding point, but this might just be dummy one.

If the top line is a passenger line, then yes, a trap point would be needed, or another set of points to form a crossover. From a previous post of yours, I think you said wagons might be parked over the middle point (the one leading to the narrow gauge), which rules out using this set of points to form a crossover. If you use a trap, this needs to be to the left of wherever wagons might be left, but if you use a crossover and extend the middle road to the left, you could leave wagons anywhere on it (but obviously there mustn't be wagons actually on the points when you want to change them to bring a train in or out).

 

If the top line is a passenger line, then depending on how far passenger trains travel along it, the right hand crossover might need to be co-acting and worked from a signal box or ground frame..

 

If there isn't a passenger line, then hand points throughout, and no trap point, would be fine, and the most likely way of working.

[Stubby47]

As can be seen from this Google Earth image, theplatform extends from berlow the overbridge for some distance along the line.

 

 

As can be seen from the 3rd pic in my previous post, I've got a point under the bridge which doesn't exist in reality (a result of compression). The platform, if I add it, will extend on the right-hand route, and passenger stock will consist of a single railcar, just poking its nose on-scene. 

[St Enodoc]

1 hour ago, Stubby47 said:

 

Correct, I was.

Crossover might be a loose term, seeing as how the points are some distance apart, but the original question could also apply to the two other points, which do appear to be a crossover ( although not actually laid yet, so could also be separated).

 

I think, given all of the above info, I can operate the points one at a time, as if they were yard points with levers, which, I think, will look more interesting. 

 

I probably also need to add a trap point between the main point and the kickback to the transfer siding point, but this might just be dummy one.

Stu, all the trap points on my layout are dummies. I have enough trouble with derailments without deliberately encouraging them.

[Nick C]

42 minutes ago, Stubby47 said:

As can be seen from this Google Earth image, theplatform extends from berlow the overbridge for some distance along the line.

 

 

As can be seen from the 3rd pic in my previous post, I've got a point under the bridge which doesn't exist in reality (a result of compression). The platform, if I add it, will extend on the right-hand route, and passenger stock will consist of a single railcar, just poking its nose on-scene. 

Given that such a platform would be for military use only, and probably quite rarely used, I wonder how much of the normal signalling regulations would have applied? They may well have just clipped any facing points for the duration of the move...

 

Still seems to be some interesting trackwork in the docks too, like this bit:

[Stubby47]

5 hours ago, Nick C said:

 

Still seems to be some interesting trackwork in the docks too, like this bit:

 

Yes, there is lots still there, and most of it still usable.

Restrictions on baseboard size has meant I am unable to replicate, even in OO9, but maybe next time...