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Help desperately needed for wIring feeds and switches on an out-and-back + continuous run layout (DC)?


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Can I ask for some help with this one? I just can’t work out what I need to do to make my layout work as I want it to. As the son of an electrician, you’d think I’d know better, but no – I followed the path of mechanical engineering and the nuances of electricity just don’t sink in I’m afraid. I’ve not been lazy – I’ve tried, really I have, but I just can’t work things out, and a solution must be possible? I wasn’t sure whether to put this in the ‘Help and Tips’  area, but here seems a better bet, so here goes…

 

My track-plan is an old C.J.Freezer favourite - an ‘out-and-back plus continuous run’. All points are PECO Insulfrog to keep things as simple as possible for my feeble mind.

As you can no doubt work out by this stage, I’m not very good at anything electrically technical, and I don’t want to get involved in the expense of converting my locomotive stock (coming up to 60 years worth in places – I started out when I was 3) to DCC (but I do realise how nice it would be – sound especially).

 

I suspect that my main existing feeds can be used, but I’m not sure – I’m quite prepared to re-visit those, as everything needs reappraisal – and I hope this is where someone here can guide me or at least clarify? It’s probably best to show the track-plan at this point:

 

LayoutSchematic3.jpg.89b9a8f3072ee081213923854caf257d.jpg

 

The main part (the continuous run bit) of the layout is complete and ‘sort-of’ operational (in a very rudimentary fashion), but the high-level terminus has been used for many years as my workbench, and I really need to get things to how they were always intended to be and build the thing! Therefore, now that the upper board containing the terminus section is to be added – well that’s where my difficulties start, as that section needs to be bi-directional, and the circuits ‘come together’ so-to-speak following a ‘reversing loop’ change of direction on the main layout. The point at ‘X’ is where I get confused. If I was to use a common return as I intended, this will lead to a ‘clash’, and I can’t get my head around a solution. Perhaps, I’m over-thinking, but I very much doubt it!

 

The layout is analogue and I would like to work out the wiring requirements for a ‘cab control’ system of working using a common return bus (although the common return bit is not mandatory, it’s just what I have read as being desirable). I hope to use rotary cab selection switches (in order to get a visual feedback on what controller is switched in for any specific section, and I anticipate that any one of three controllers can control any cab on the layout (either main circuit or terminus). I always intended that, in practice, controllers one and two would be used for the main circuits, and controller three could be used for terminus ‘pottering’ movements. But any controller could be used to start/terminate trains in/out of the terminus.

 

It would be good if the ‘reversing loop’ (effectively a long crossover) could be used without having to stop the train in order to throw a DPDT switch, but I’ve got a complete blank on that too.

 

At present, I have two (double Gaugemaster) panel mount controllers using separate transformers, but one question that I also can’t resolve is if a third transformer would be required for the third (a single Gaugemaster) controller, as I have seen various references stating that a short could/would occur if the same power supply is used between sections that could overlap.

 

To see me into my dotage, I would really be most appreciative if someone could spare the time to give me some help with a wiring diagram that shows feeds and (types of) switches - something ‘done proper’, in order that I will have something reliable and properly designed for the future. Something where I wouldn’t have to crawl underneath the layout to correct faults that I had built in years before - ‘cos I can’t bend like I used to…

 

Sorry for being a numpty.

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2nd edit as I've noticed something important. Do you intend putting in any more crossovers between red and yellow loops? If no you can simplify the wiring significantly.

Another question, do you think you might consider DCC in the future - this could make a big difference in how you wire this layout.

 

I would suggest that you sort out your ovals and return loop before progressing any further with your extension/terminus.

 

 

At point X you have a problem in that the crossover creates a short between the red & yellow lines. You MUST isolate both rails in between the two points.

 

 

Edited by kevinlms
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There are two, possibly more, separate things here.

 

Firstly the reversing loop. As its so long, you can arrange to break the track up into sections so that relays flip the points and the power. Someone here will have done this, for certain.

 

Second the power to the upper level which is basically a set of sidings, there is no reversing loop there, but a separate power feed will be required to the turntable area. Thats not the same as having a third controller, which is also possible. You need switches and insulated joiners in various places to prevent power being applied where you dont want it, and on a layout of this size that is going to be a fair challenge. If you are thinking about three controllers, which I had on my previous layout, you really should be thinking about dcc although I appreciate with heritage rolling stock this may be a problem. Otherwise remember you only have 2 hands and there are points to operate - you dont say if they are motorised, but its either a switch or hand one way or another. I found this mode of control too restrictive which is why I am switching. 

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1 hour ago, kevinlms said:

Do you intend putting in any more crossovers between red and yellow loops? If no you can simplify the wiring significantly.

Another question, do you think you might consider DCC in the future - this could make a big difference in how you wire this layout.

Thanks for the reply. No, the only crossover is that marked 'X' and ther return loop itself.

 

Of course, there are crossovers in the terminus itself, which I'm hoping 'could' be powered by the red or yellow loop controllers, so that a train could directly leave the terminus, and proceed around the red loop (e.g. cab1), leaving me to 'potter' in the terminus (e.g. cab2), until it was time for the train to 'reverse loop' to the yellow (another train could depart the terminus at this stage). The train could then proceed round the yellow loop (e.g. cab3), until time to be driven directly back to the terminus. Cab 2 would be switched out (or restricted) if cab 1 or 3 was in operation. I was hoping cabs 1, 2 and 3 would be interchangeable with what block they were controlling.

 

In answer to your second question, although I can fully see the benefits of DCC, I can't justify the expense of chipping up to 60 locomotives, plus the control systems, plus the technical challenges of DCC comes into play as well - I'm not at all au fait with the technology. Really, I just want to get things working on DC properly, so I can concentrate on what I enjoy - the scenic side of things.

 

1 hour ago, RobinofLoxley said:

Firstly the reversing loop. As its so long, you can arrange to break the track up into sections so that relays flip the points and the power. Someone here will have done this, for certain.

Thanks RobinofLoxley! I'm hoping someone might tell me how! (not that relays aren't a mystery to me too...)

1 hour ago, RobinofLoxley said:

you dont say if they are motorised, but its either a switch or hand one way or another

They are motorised.

 

I understand I am restricting myself, but DCC doesn't stack up for me (price-wise, and at my age), tempting though it is.

 

Appreciate the replies thus far though, thanks!

 

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If I were doing this I would go back to 1st principles.  First, I would decide that I am going to use cab control.  Then I would decide how many cabs - I think you will need at least 4.  Decide which is up and which is down.  Next is to divide the layout into blocks such that each block is physically independent of each other.  Note: you can use multiple blocks to achieve continuous running through the reverse loop.  For example I see the loco yard as one block,  The green and orange is possibly 4 blocks.  A quick look says a redesign of the terminus may be necessary.  It will take a bit on mental doodling time but I think at first glance you can do everything you want

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I'm not quite sure how applicable this is to your layout but I'll post anyway in the hope that there might be something useful in it. Your layout is much more complex than mine but generally works on a similar principle; a train can leave the terminus, do a few loops of one side of a double track main line, cross over to the other track going the other way, then back to  the station.

 

My double track main lines are wired so +ve is clockwise on one, and anticlockwise on the other; this means no electrical trickery is required to use the crossover. This is the key bit. The feed to the terminus however has a DPDT switch used to flip the polarity so +ve is outbound when connected to the up loop of the main line but inbound when connected to the down loop.

 

This way, applying +ve to a train in the terminus propels it forwards onto the up loop, across the crossover to the down loop, then before it returns to the terminus the terminus polarity switch is flipped so the train can then return to where it started, all without stopping the train or interrupting its power feed in any way.

 

My layout uses a single line to the terminus, so the polarity of the terminus can be flipped without having to worry about whether there are trains on inbound or outbound lines, so yours is a little more complicated, but I think it still works for one train arriving or leaving at a time. If you separate the terminus into its own section just below the crossover at 'X' that you can flip the polarity it would work. You would have to do something a bit cleverer to allow two trains to leave and arrive at the same time - perhaps a flippable section for both terminus lines - but it's a starting point.

 

On my layout a single slip and turnout is used to connect the terminus to the up or down loop; the setting of these is (well, will be, when I've finished it!) used to set the polarity of the terminus so it matches the track it is currently connected to. It is split into four sections (up loop, down loop, crossover, terminus), each of which can be controlled by one of two controllers, so a controller can stay with a train as it circulates round the layout even as other trains are moving in other sections.

 

You don't have this problem as yours uses a grade separated crossing, but on mine the fun bit is that going from the terminus to the "up" loop involves a flat crossing to get over the "down" loop; it would make for rather a large crash if you time it badly :-) 

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11 hours ago, Theakerr said:

If I were doing this I would go back to 1st principles.  First, I would decide that I am going to use cab control.  Then I would decide how many cabs - I think you will need at least 4.  Decide which is up and which is down.  Next is to divide the layout into blocks such that each block is physically independent of each other.  Note: you can use multiple blocks to achieve continuous running through the reverse loop.  For example I see the loco yard as one block,  The green and orange is possibly 4 blocks.  A quick look says a redesign of the terminus may be necessary.  It will take a bit on mental doodling time but I think at first glance you can do everything you want

Thanks - some interesting ideas there, although I'm not 100% sure why 4 cabs? (It's not you - it's me :)).

Also, I'm curious as to where and why a redesign of the terminus might be necessary?

I'd be loathe to do that by the way, as it matches my prototype (...to a degree anyway - it's been flipped and mirrored, and lost one platform road - further mangling might mean its unrecognisable).

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10 hours ago, Phil Himsworth said:

I'm not quite sure how applicable this is to your layout but I'll post anyway in the hope that there might be something useful in it.

Very useful Phil - it's going to take some mulling over, but its good that you've had some experience of a similar plan and it's challenges, although I think having a double track to the terminus increases the complexity somewhat for me.

 

10 hours ago, Phil Himsworth said:

My double track main lines are wired so +ve is clockwise on one, and anticlockwise on the other; this means no electrical trickery is required to use the crossover. This is the key bit. The feed to the terminus however has a DPDT switch used to flip the polarity so +ve is outbound when connected to the up loop of the main line but inbound when connected to the down loop.

This bit interests me, thank you - I'll take some time now to see how it might help me in my application.

 

And thanks to all who have taken the time to write thus far - it's appreciated.

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Hi Billy,

 

It's not at all difficult to automate the reversing loop. It just needs a method of detecting when the train gets to a particular place in the loop. There are lots of ways to do that. You could even do it just by pressing a button.

 

When the train is detected two things happen simultaneously. The output of the controller is automatically reversed with a relay and the feeds to the loop are taken from the output end of the loop rather than the input to the loop. This is done with a second relay.

 

Cheers,

Andy

 

 

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Thanks for the reply Andy. I think I am getting somewhere, as I have now got the +ve and +ve rails aligned everywhere on my plan (with the caveat that the reversing loop switches polarity somewhere along its length) so your reply is quite timely.

The only thing that I don't get is if the controller is reversed, doesn't that mean that the train then goes backwards? Or does the relay take care of things? Apologies if this is basic stuff.

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2 hours ago, billy_anorak59 said:

The only thing that I don't get is if the controller is reversed, doesn't that mean that the train then goes backwards?

The controller is reversed, but the power is now fed from the loop on which it is now running in the opposite direction, so the two reversals cancel each other out and the train keeps going the same way.

 

14 hours ago, AndyID said:

When the train is detected two things happen simultaneously. The output of the controller is automatically reversed with a relay and the feeds to the loop are taken from the output end of the loop rather than the input to the loop. This is done with a second relay.

Does this not require that the train is stopped, or that a brief interruption of supply is acceptable? Relays would not be fast or synchronised enough; I would have thought the only way you might be able to switch the polarity and feeds simultaneously with no observable interruption would be some kind of solid state device; I don't know how I would do it. 

 

This is why I reversed one of the loops so the reversing loop is not a reversing loop electrically; it is the terminus that then needs its polarity switched depending on the loop to which it is routed, and that can be done when the train is elsewhere so at no point does the supply to the train itself need to be switched.

 

 

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2 hours ago, Phil Himsworth said:

he controller is reversed, but the power is now fed from the loop on which it is now running in the opposite direction, so the two reversals cancel each other out and the train keeps going the same way.

Ah-ha! The light is slowly dawning... :)

Thanks for that - much appreciated!

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Hi Phill,

 

I used the relays method about 25 years ago and there was no perceptible change in speed. It's best to use two identical relays and configure them such that they both pull-in or drop-out at the same time.

 

Personally I think it's a good idea to take care of the problem at the reversing loop to keep crossover operations simple.

 

Cheers,

Andy

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Its about concept not wiring.    From just beyond crossover x back round the layout and back to the same place just short of crossover x on the other line one can connect the controllers so forward means the train runs forward anticlockwise around the red tracks forward around the blue reversing loop and forward clockwise around the yellow tracks leaving plenty of time to reverse the DPDT switch on the terminus controller so forward  drives the train into the terminus.   The trick is then to change the DPDT switch back so the shunting is done with forward being away from the terminus.   Crossovers between tracks complicate things but if you can live with the concept of forward being forward as per DCC its quite straight forward.

If you can't at some stage you have to stop the train to change the direction of the controller or drive from one controller to another, which is it self awkward/ complicated.

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Hi Billy,

 

What are the approximate dimensions of your layout? I'm assuming it's 00 is that correct? What's the longest train you run (number of coaches?

 

Cheers,

Andy

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12 hours ago, DavidCBroad said:

Its about concept not wiring.    From just beyond crossover x back round the layout and back to the same place just short of crossover x on the other line one can connect the controllers so forward means the train runs forward anticlockwise around the red tracks forward around the blue reversing loop and forward clockwise around the yellow tracks leaving plenty of time to reverse the DPDT switch on the terminus controller so forward  drives the train into the terminus.   The trick is then to change the DPDT switch back so the shunting is done with forward being away from the terminus.   Crossovers between tracks complicate things but if you can live with the concept of forward being forward as per DCC its quite straight forward.

If you can't at some stage you have to stop the train to change the direction of the controller or drive from one controller to another, which is it self awkward/ complicated.

Yes,  I agree with David. 

Everything beyond the X DOESN'T need any polarity reversal, not even the blue track.

If you apply positive voltage to the right hand rail, the loco will run forward (this is standard convention), all the way from the X, until you get back, including going around the apparent reversing loop. It is only apparent, because there is no point of short circuit, until you get back to the X.

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12 hours ago, AndyID said:

What are the approximate dimensions of your layout? I'm assuming it's 00 is that correct? What's the longest train you run (number of coaches?

Hi Andy - the layout is approx 12' x 8'. The longest train will be limited to only 4 (maybe 5 at a push) coaches - mainly because of the physical size constraints, but also due to the 1 : 30 incline from the through station to the terminus.

 

Thanks to all who have responded, it's all very much appreciated!

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Thanks Billy. Got the idea.

 

As usual there is no right way or wrong way to do it. There are different ways each with potential puts and takes.

 

You can either think of it as a terminus attached to a very big and slightly complicated reversing loop (call it A) or you can see it as a terminus connected to a long double track with a reversing loop at the very end (call it B) :)

 

My personal preference is B for a couple of reasons. It would allow the addition of more crossovers without much difficulty. For example, maybe I'd want to allow some interesting shunting moves for the sidings at the through station. The other reason is that the direction switches on the controllers would always indicate the intended direction. Moving the switch left will make the train move to my left and vice versa. B is also fully compatible with common return wiring (apart from a section in the reversing loop.)

 

On the other hand A is perhaps simpler because it does not need a means to flip the polarities of the section in the reversing loop (not that it has to be very complicated). The difference is that the controller switches (or knobs if they are center-off controllers) do not directly relate to the physical direction of travel on the layout which can be confusing (I know it confuses me).

 

Then with A things get more complicated at the terminus. In the terminus area the controller direction will actually indicate the direction of travel relative to the operator but that is in conflict with the controllers powering the loop. That's probably not a big deal if the trains run more or less straight through but it can make any shunting operations a bit confusing. A is not fully compatible with common return in so far as the terminus area and the rest of the layout must "float" relative to each other. That would make cab-control rather complicated and I think it precludes common return.

 

I probably missed a few things but I'm sure someone will let me know if I did :D

 

Andy

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