Isolating a passing loop

Dan

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My take on the original question as trains run in opposite directions is what are you using to run your trains. DCC makes running traIns in opposite directions very easy as CV 29 contains the direction, and then run this loco on DC with a standard loco with just 2 joiners on each track segment (4 total). For DC only engines one must tuse 2 joiners on all rails (need 8) but one engine needs track power inside engine reversed. Bachmann had many locos that had a switch that did this and was labeled for G or standard, standard being the large scale reversed power.
 

playmofire

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My take on the original question as trains run in opposite directions is what are you using to run your trains. DCC makes running traIns in opposite directions very easy as CV 29 contains the direction, and then run this loco on DC with a standard loco with just 2 joiners on each track segment (4 total). For DC only engines one must tuse 2 joiners on all rails (need 8) but one engine needs track power inside engine reversed. Bachmann had many locos that had a switch that did this and was labeled for G or standard, standard being the large scale reversed power.
I'm using DC, not DCC. One end of each passing loop passing loop is isolated from the oval of track by a point which depending on its position either cuts off power from the loop or allows on to the loop. At the other end of each loop is a signal which does the same thing as the point but I think I see your point,

The layout wiring should work as follows.

When one train is running clockwise round the oval of track, both sets of points are set to isolate the loops as are both signals; the second train is thus isolated on one of the loops.

When the train on the oval is to end its run by returning to the loop it started from, the point for the that loop is switched to allow power on to the loop so the train can enter it; when the loco crosses the split track at 2 on the diagram in post 13, it stops and the point is then switched back to the oval. Both loops now have trains on them and both loops are isolated from the oval.

Now, the point for the other loop is switched so there is power to the loop, and the signal is then set to go, allowing the train to enter the oval, after which the point is set to isolate the now empty loop and the signal is set to stop. This train is now running counter-clockwise (the trains are set for their direction of travel when first put their respective loop).

The counter-clockwise running can certainly be achieved in two ways, by reversing the wires to the pickups on one loco (I have a loco which came second hand wired like that - well, actually not so much wired like that as that the previous owner had removed the motor and then put it back in the other way round, as is possible with Playmobil locos which this one is), or just running one train with the loco running in reverse - both are tank engines, so a common practice.

Another possibility might be to have two controllers connected with the connections to the tracks reversed for one of them. However, I suspect that it would be sensible to have some means of isolating the controller not being used, e.g. by a simply throw switch.
 

Paul M

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Wouldn't putting the voltage feeds from the 2 controllers on the passing loop, isolate one of the controllers when the points were set against it?
 

playmofire

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Wouldn't putting the voltage feeds from the 2 controllers on the passing loop, isolate one of the controllers when the points were set against it?
The controller(s) will be connected to the oval. I'm not even sure two controllers will be needed, thinking further on Dan's post. I'm going to set up a test tomorrow and will report then.
 

dunnyrail

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I'm using DC, not DCC. One end of each passing loop passing loop is isolated from the oval of track by a point which depending on its position either cuts off power from the loop or allows on to the loop. At the other end of each loop is a signal which does the same thing as the point but I think I see your point,

The layout wiring should work as follows.

When one train is running clockwise round the oval of track, both sets of points are set to isolate the loops as are both signals; the second train is thus isolated on one of the loops.

When the train on the oval is to end its run by returning to the loop it started from, the point for the that loop is switched to allow power on to the loop so the train can enter it; when the loco crosses the split track at 2 on the diagram in post 13, it stops and the point is then switched back to the oval. Both loops now have trains on them and both loops are isolated from the oval.

Now, the point for the other loop is switched so there is power to the loop, and the signal is then set to go, allowing the train to enter the oval, after which the point is set to isolate the now empty loop and the signal is set to stop. This train is now running counter-clockwise (the trains are set for their direction of travel when first put their respective loop).

The counter-clockwise running can certainly be achieved in two ways, by reversing the wires to the pickups on one loco (I have a loco which came second hand wired like that - well, actually not so much wired like that as that the previous owner had removed the motor and then put it back in the other way round, as is possible with Playmobil locos which this one is), or just running one train with the loco running in reverse - both are tank engines, so a common practice.

Another possibility might be to have two controllers connected with the connections to the tracks reversed for one of them. However, I suspect that it would be sensible to have some means of isolating the controller not being used, e.g. by a simply throw switch.
What you are describing is perfectly possible with LGB EPL on analogue. The LGB point motors with track activation sensors (activated by a magnet under the engine) can with the add on DPDT switch act as a relay and thus reverse a train. They can also isolate a loop and even thriw points and signals. I got my one working completely automated but only one way, I never put the time in to experiment to get the train reversing or changing points to use the loops. See below.

 
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Gavin Sowry

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I would interrupt the two inner sides of the loop, then the continuity of the outer running rails isn't broken :nerd::nerd:
That's what I've done for all my sidings on Taita Gorge.
 
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Gavin Sowry

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As @Software Tools says the LGB points are not isolating. If you have 2 trains and you wish to swop between the 2 running you will need 4 isolators and a switch for each section as shown below. You can with LGB EPL easily automate this setup.
View attachment 315799
Apart from changing this to isolating the inside tracks, what's missing from the drawing is the wires feeding the power to the switches (pl). Working 'backwards', connect the isolated rail to a simple on/off switch, then run a wire from the switch to any powered rail of the same polarity. Do this for both isolations. To operate, just turn the isolating section on or off as needs be. Simple, should not cost more than a few quid tops. I don't know why folks make things too complcated/expensive
 

dunnyrail

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I don't know why folks make things too complcated/expensive
There are those that enjoy the complexity of wiring and making things automated. It is not entirely clear what the questioner has in terms of interest of those items thus I imagine most repliers are trying to give their take on the question. On my wiring diagram I tended to assume knowledge of LGB points and simple wiring, you have so eloquently described the need for a simple solution in your latest reply.
 

playmofire

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I appreciate the time and thought people have put into responding to my question but things seem to have become complicated I suspect because the writer is responding to the latest in the thread without taking account of all that has gone before or because the writer is looking to a more "complicated" approach to what I am proposing. I think I have the answer to my question but, meanwhile, here's a recap drawing together the various points which have been raised.

I'm planning a layout for the last Kirkbean Playmobil Exhibition including two passing loops on an oval, at any one time, one oval will have a train parked on it and the other will be empty while its train circulates the oval. The idea is that a train will run clockwise for a while and then be parked on the empty passing loop and the other train will then be released from its passing loop and circulate anti-clockwise, being returned to it after a few circuits and so on.

Clearly, the passing loops need to be isolated and I originally thought of doing so through the points at each end of the passing loops. However, it occurred to me that if there were an isolating point at the entry end of each passing loop and an LGB semaphore signal US style at the exit end of each loop, I could isolate the loops that way and release the trains under signals.

. There will be a passing loop each side of the oval, one for trains running clockwise (call it the North Loop) and one for trains running counter-clockwise (call it the South Loop). In each case, the entry to the loop will be controlled through an electrically operated point connected to a 1015U split track. The exit side will have an electrically operated point and an electrically operated signal, the signal at stop being the means of isolating the train from the exit end through a1015U split track and from the entry end similarly.

I know it is possible to drive the signal via the exit point, but as the loop will be used for parking a train while another train runs round the oval in the opposite direction, I want point control and loco power to be separate.

Here's the track layout for the North Loop, repeated for the South Loop suitably modified:

Kirkbean passing loop clipt.JPG

The train approaches from the left and enters the loop. The split track at 1 is transmitting power and so the train continues until the loco crosses the split track at 2 and then stops. The loco is an LGB Spremberger and a half rail length between the split track at 2 and the split track at the signal at 3 is enough to isolate it.

After the loco stops at the signal, the entry point is switched back to the mainline, so the loop is now isolated from both ends.

At the passing loop on the other side of the oval, there is a train waiting to be released to travel counter-clockwise and this is done simply by releasing the signal at the exit end of the passing.

Once a train is on the main line running in either direction, both loops are fully isolated, by a point at the entry end and by the signal at the exit end.

The power supply is to the continuous, inner loop in this, all the interruptions via split tracks being on the isolated, outer passing loops.

In the light of Dan's post (#21), under DC there is no problem running a loco clockwise and then (after that loco has been isolated on a passing loop) running another loco anti-clockwise; all that is needed is to remember that if turning the control knob on the controller clockwise sends a loco clockwise and forwards around the oval, turning the control knob anti-clockwise sends a loco facing in an anti-clockwise direction forwards around the oval.

Complex to describe but not to wire up or to operate.

I take Dunnyrail's point about using EPL to its fullest, so if setting up and testing go smoothly I may investigate interlinking some operations between the two passing loops, although at some point I will need to intervene to decide when a train on the continuous loop is to return to its starting loop.
 

PhilP

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I don't think you need a gap at point 1..
If you enter from that end, the siding can be live to point 2,which can be an insulated rail joiner a loco-length back from point 3.

Use an auxiliary switch on the exit point, to feed power to an auxiliary switch on the signal, which powers the track between 2 and 3.
Both the point and signal need to be set, for power to be on the short length of rail, and the loco leave the siding.


If the exit-point, signal, or both are against the loco, then the length of track 2-3 is dead, and the loco will stop on passing point 2, as it runs along the siding.

PhilP
 

playmofire

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I don't think you need a gap at point 1..
If you enter from that end, the siding can be live to point 2,which can be an insulated rail joiner a loco-length back from point 3.

Use an auxiliary switch on the exit point, to feed power to an auxiliary switch on the signal, which powers the track between 2 and 3.
Both the point and signal need to be set, for power to be on the short length of rail, and the loco leave the siding.


If the exit-point, signal, or both are against the loco, then the length of track 2-3 is dead, and the loco will stop on passing point 2, as it runs along the siding.

PhilP
I think with the entry point I'd prefer to keep the insulation as a safeguard. As regards the signal, if the split track at 2 is removed, then the loco has passed the signal (partially at least) before it stops. The exit point is only isolated by the signal, so changing the signal can be used to change the point using the auxiliary switch on the signal, or the auxiliary switch on the point can be used to change the signal. (In fact, I suppose I could just have a manual point there and rely on "push-through".)