Signal interlocking and level crossing

[Halton Boy]

Hello every one

I am now building my O gauge layout based on my friends, late husbands layout.

I have some Colbalt signal levers and Colbalt analogue point motors.

 

I am going to have a form of signal interlocking using the switches on the levers.

The 12volt supply goes to lever 14 which operates the crossing gates. When this lever is in the frame there is a 12volt supply to lever 9 the FPL.

When lever 14 is pulled there is no supply to the signals or point in this area.

When in the frame lever 9 supplies signals 6 and 11only for route 6.

When lever 9 is pulled the 12volt supply is switched to signals 7, 12 and point 8.

These can then be used to set route 7.

I am not sure if it is possible to operate the crossing gates with servo motors.

The crossings that I have found online are Peco LK-750 level crossing gates and Skytrex 7/237 level crossing gates.

If it is not easy to motorise the crossing gates I could wire in an LED next to the signal lever frame to indicate that the crossing gates are closed to trains.

It might be possible to then shut the gates by hand.

The rest of the layout would operate as normal with signals 6 and 7 stopping train movements past those signals.

It would be up to the driver (me) to not run past the signals and hit the gates.

I could supply the lever frame via a micro switch on hand operated crossing gates, but this would be a part that could fail.

What do you think of this interlocking plan?

Is it easy to motorise O gauge level crossings?

Thank you for your help.

Ken

 

 

Edited May 5 by Halton Boy
Text added

[Halton Boy]

Hello everyone

Here is the other part of the layout that also uses Dapol signals.

Point 3 acts as a trap for passenger trains that pass signal 15.

When lever 3 is in the frame ground signals 2 and 5 can be operated.

When lever 3 is pulled then goods signals 1 and 15 can be operated.

 

A goods train that has come from the direction of signals 6 and 7 and wants to reverse into the coal siding, would require point lever 3 and signal lever 15 pulled.

It would then travel past signal 1 and stop.

Signal lever 15 would be put back.

Point lever 3 would be put back and ground signal 2 would be pulled allowing the train to reverse into the coal siding.

All signals are by Dapol.

I think this should work.

Has anyone used Colbalt signal box levers in this way?

Thank you for your help.

Ken

Edited May 5 by Halton Boy
Text added

[Ray H]

I think you may have misunderstood the use of trap points.

 

Assuming that the line is used by passenger trains it would be more usual to have No. 3 point's lever back in the frame which leaves the points set for the route to/from the curve at the bottom of the plan.

 

No. 3 points would only be reversed/pulled/out of the frame for moves into/out of the coal siding. The coal siding would need a trap point to stop anything unintentionally trying to leave the coal siding, the trap point in the siding protecting the main/running line from runaway wagons for the siding. No. 3 points will, when normal/set for the curve, stop unwanted movements into the siding.

 

Nos 1 & 15 signals would need No. 3 points normal before those signals could be cleared and Nos. 2 & 5 signals would need No. 3 points reversed (and the trap points in the siding set for trains to run in and out of the siding.

 

Whilst it may be possible for signals 1 & 15 to be pulled off (show proceed) at the same time - often done when the box is closed, signals 2 & 5 could also be cleared in unison or independently (with 3 points set appropriately etc.) but you can't have either or both running signals showing proceed at the same time as either or both of the shunting signals are clear (or vice versa).

[Cwmtwrch]

2 hours ago, Ray H said:

Assuming that the line is used by passenger trains it would be more usual to have No. 3 point's lever back in the frame which leaves the points set for the route to/from the curve at the bottom of the plan.

It isn't, hence the ringed signals. You may like to have a look at https://www.rmweb.co.uk/forums/topic/185911-signals-for-a-single-line-junction/, which gives the background.

[Halton Boy]

Hello Ray

This plan is very much like Coombe Junction. Passenger trains do not pass signal 15.

The plan comes from the post "Signals for a single line junction" that I did earlier.

In that post I was told that a trap point was not required at point 3 because that point would act as a trap because the point would be set normally to the siding.

From signal 15 the line is goods only.

With point 3 set to the siding it would protect the passenger train at the halt.

In reality the line would be one engine in steam.

I am sorry I did not make that clear.

This is the complete plan.

I would run a push/pull passenger train or rail car to the halt via signal 11 and back out via signal 12.

I could also shunt the yard with a goods engine that did not pass signal 1.

Thank you for your comments.

So can I motorise O gauge level crossing gates?

Will the Colbalt signal levers work well this way?

I know that a lot of people would not bother, but I would rather be a signal man than a train driver. 

Thank you all for your help.

Ken

[Michael Hodgson]

It's not difficult to work level crossing gates with servos.  Note that as the swept arcs on both the Peco and Skytrex crossings conflict with each other, you have to move one then the other.  If they were hand worked, thus would be true on the prototype also of course.

 

If they were worked from the box they would be worked by a gatewheel, and there would usually be four gates whose swept arcs do not intersect.  Whether the gates are hand or wheel worked, the brown lever is a lock to hold the gates in place (and release the interlocking on relevant signals).

 

I would wire the brown lever to isolate traction supply in the vicinity of the crossing, as otherwise its accident waiting to happen, rather like not putting buffers on a siding close to the edge of the baseboard.

 

 

 

4 hours ago, Halton Boy said:

When lever 3 is in the frame ground signals 2 and 5 can be operated.

When lever 3 is pulled then goods signals 1 and 15 can be operated

 

 

 

That should read 2 OR 5, 1 OR 15 - signals in opposite direction on same track are interlocked against each other.

 

Likewise you would be able to clear one of the four signals 6, 7 11 & 12 at any one time and then only with the points correctly set, the crossing gates locked and for movement left to right the FPL lever pulled.

Edited May 5 by Michael Hodgson

[Jeremy Cumberland]

9 hours ago, Halton Boy said:

The 12volt supply goes to lever 14 which operates the crossing gates. When this lever is in the frame there is a 12volt supply to lever 9 the FPL.

There is no reason I can see to have any interlink between 14 and 9. If signals 6, 7, 11 and 12 are all at danger, you can move the points and work the crossing gates to your heart's content.

 

9 hours ago, Halton Boy said:

When lever 14 is pulled there is no supply to the signals or point in this area.

No supply to the signals is fine, but no supply to the points would be rather restrictive. I think, even in a model.

 

9 hours ago, Halton Boy said:

When in the frame lever 9 supplies signals 6 and 11only for route 6.

When lever 9 is pulled the 12volt supply is switched to signals 7, 12 and point 8.

 

I don't understand what you are aiming for here. Is lever 9 in the normal or reverse position to lock the points? From your second sentence, it looks like pulling 9 unlocks the points, but really the complexities of interlocking, even in such a simple installation as this, don't lend themselves to only using the switch contacts contained within the Cobalt lever units. Instead you need something capable of more complex logic, such as multi-contact relays or some form of computer control with an input module that detects each lever position.

 

There is, of course, a fundamental problem with just using electrical switching rather than physically locking the levers in that it is all too easy for lever positions to be out of correspondance with the physical points and signals on the layout. You might have correctly set a route for a departing train using signal 7, with 7 reverse, 8 reverse, 9 in whichever position locks the points and 14 in whichever position locks the gates across the road. You might then set a route for an incoming train from 11, but forget to put signal 7 to danger first. So you change 9 and 8 and pull 11, but nothing happens. You then realise you didn't return 7 to danger, so you do that, but what happens now? Perhaps nothing, depending on how you have interlocked 8 and 11 - will the points change with lever 11 reverse (even if the signal on the layout is still at danger)? I think I would find this very confusing.

 

Several people have come up with ways of physically locking levers so that you can't, for example, move lever 9 with lever 7 reversed, but I don't think there is any way of putting a mechanical or electrical lock on a Cobalt point lever. I could be mistaken though.

[Ray H]

13 hours ago, Cwmtwrch said:

It isn't, hence the ringed signals. You may like to have a look at https://www.rmweb.co.uk/forums/topic/185911-signals-for-a-single-line-junction/, which gives the background.

 

Apologies, my mistake. I had failed to note the ring on signal 15.

 

Presumably, working the coal siding would be self contained to the freight section of the line, rather than using the halt or was that not how it was done? 

[Halton Boy]

Hello everyone

Ray the layout is based on Coombe Junction but it is not the same.

Coombe Junction did not have a coal siding.

My layout is going to be called Weston Turville Junction. 

I imagine there is a line from near Wendover station and a line from near Stoke Mandeville station which meet at  Weston Turville Junction. The lines were never built.

 

Michael and Jeremy what you have said is correct.

Here are two new plans with the revised ideas:

I think I will go with the second plan and leave the crossing gates closed to road traffic.

If the relay suppling the track failed the track would remain energised.

In the second plan lever 14 has been used to make up three levers for the yard.

Each lever operates both points together. Lever 1 operates points 1 and 1.

 

You are both right about the interlocking.

With lever 9 in the frame you can operate signal 6 or 11. You have to remember to set the signals back to stop before pulling lever 9 which then lets you operate point 8 and signal 7 or 12. This is not ideal.

With lever 3 in the frame you can operate ground signal 2 or 5. You would have to put these back before pulling lever 3 to change the points and then pulling lever 1 or 15.

The brown supply line to lever 15 should not be there, see below.

 

Here is a picture of the Colbalt levers:

I notice in the image above that the levers are numbered 1-3-4-2 is this normal?

If it is I could reorder the levers in the frame to give physical interlocking using strip on one or more levers. 

It would be possible to glue a piece of strip or solder strip to one lever so that the other lever cannot be pulled until the lever with the strip has been pulled.

This does not look a very elegant solution.

I do not want to go down the route of computer control as I have the analogue levers and point motors.

Thank you for your help.

Ken 

 

Edited May 6 by Halton Boy
Text added

[Ray H]

Could you alter the numbers around so those that you physically want to mechanically lock another have adjacent lever numbers?

[Halton Boy]

Hello Ray

I think the lever numbering is done in a conventual way.

The Distant signal would be the first and last levers in the frame, then the running signals would be next. Home, Advanced starter, Starter and so on.

I have put the low numbers starting from the goods yard in the left of the frame.

The high numbers starting from the two right hand lines in the right of the frame.

 

I am sorry but there is a mistake in the lever frame plan, of plan two.

It should be this, with no 12 volt supply to lever 15:

FPL lever 9 locks the points 8. So that interlock works.

It is the locking of the signals that is not perfect.

The interlocking does not stop me from pulling a signal for the wrong direction.

So 7 instead of 12 for a train travelling to the halt.

Also I could forget to put a signal lever back after the train has passed.

If I put FPL lever 9 back first there would be no supply to points 8 and signals 7 and 12.

I would have to work methodically putting the signal levers back, then the points and last the FPL lever.

Thank you for your help.

Ken