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Discussion Starter · #1 · (Edited)
Hi All:
I'm in progress expanding my layout by adding another loop. I'm currently running one Trackside unit to control the current loop ("loop 1"), and am going to add a second trackside unit to control the new loop ("loop 2"). I've decided that I don't always want to carry two trains out, so it would be nice to flip a few turnouts and have a crossover between the loops so one train can ride over every part of the layout. Here's what the crossover looks like:
Road surface Track Plant Urban design Slope

There are insulated rail joiners coming off of the turnouts on the left side (existing loop 1 mainline)

Here's an overall view of what this section of track will look like when completed, just for reference:
Plant Train Land lot Urban design Grass


Anyways, my concern is electrically. I know the Trackside units are sensitive to being backfed by power. As such, I've decided I would control the power outputs by a DPDT switch. Sorry for the crude drawing below, but I'd wire it up like this:
Handwriting Green Product Azure Font


Where left position of the DPDT switch would allow one Trackside unit to control the whole layout. Position two would isolate Loop 1 and Loop 2, and Trackside unit 2 would control Loop 2. So, my concern is when I'm in position two and running both loops independently. There is still a small chance something could "pick the points" and begin crossing over to Loop 2, then act as a conductor and possibly backfeed one trackside unit or the other, or worse when the polarity is different between loop 1 and 2 (short out one of my locomotives). Other than isolating a larger section of track (for example, making the siding "dead rail" while DPDT is in position two, which is not desirable as I like to park locomotives there), do any of you have any ideas on how I can provide better protection for my locomotives and trackside units should an inadvertent crossover occur?

As a side note, about half of my locomotives have Revolution onboard installed, the other half do not (and probably will not) get onboard installed in the future. This is what makes the trackside units very appealing and useful to me.
 

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Discussion Starter · #2 ·
Also, I wrote JK at Revolution about this. His response was short,
"The BASE receiver is designed for a single loop.
currently, there is no workaround for that."

That does not really help for what I'm trying to accomplish, other than highlight the need to isolate things enough to provide a good level of protection from the likelihood of backfeeding and or shorting.
 

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Super Modulator
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Just keep the throttle settings and of course the polarity correct when crossing over when both loops are enabled.

A smart thing to do would be only cross over when you are set for one controller to both loops.

Just insulate the "parking track", the second from the right from the loop 2, and feed loop 2 all the time.

Simple.

center off will be "park"

Greg
 

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Discussion Starter · #4 ·
Thanks for your feedback, Greg.

A smart thing to do would be only cross over when you are set for one controller to both loops.
This is precisely what position one is for, and my intention is that I would NOT crossover unless in position one. Essentially in position two, I would want to use the siding for Loop 2 (as my primary loop) and not for Loop 1.

Just for clarification.... your suggestion is to deviate from what I have above, and always have Loop 2 controlled by Controller 2, Loop 1 by Controller 1, and use the DPDT switch to control which Loop will power the siding instead? Center position being deadrail..... position one being Loop 1 powers the siding, Position two/loop 2 powers it.....I do like this idea as it gives me the option to park/deadrail the siding, but I am concerned about making sure my polarity is correct in crossover ops with this arrangement (it is almost too easy to change directions on the receiver/transmitter, I'm more concerned I or my little ones might inadvertently change the direction in crossover ops). Or did I misunderstand your suggestion?

Mentioning the little ones, they also love to go and flip turnout mechs on me.... that is another reason for my concern and wanting to put some protection in.
 

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Discussion Starter · #5 ·
Following on my last reply, I suppose I could introduce a second DPDT switch, which would allow me to control which loop powers the siding. It is one more thing to remember to flip, but that might not be a bad measure and may give me the protection I'm looking for. I'd wire it as mentioned in my post above. Of course in DPDT position one, the siding would be dead unless DPDT switch for siding is selected to Loop 1. Maybe I should make another rough drawing to visualize it better....
 

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I just run a common ground for my three trackside Train Engineers and separate the reailroad into 21 blocks. You could also do this with just two blocks.

If a train crosses over between two power parks and they are set to the same polarity, the train will simply run at the speed of the higher of the two voltages.

If a train crosses over between two power packs and they are set to different polarity, the train will do a "cha cha" back and forth. The few times that this has happened in the last 24 years, I don't think this has ever tripped the circuit breaker.
 

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Discussion Starter · #7 ·
SUPER rough drawing, sorry all for the very squiggly lines..... hope its clear enough to atleast follow. This would introduce the DPDT to control the siding, pick which loop powers it or center deadrail. Of course, for Loop 2 connections to this DPDT, that would be AFTER the first DPDT, so if DPDT 1 is in position 1, Loop 1 would power the siding in both DPDT position one and two. Center would be deadrail of course.
Rectangle Font Parallel Gas Slope
 

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Discussion Starter · #8 ·
I just run a common ground for my three trackside Train Engineers and separate the reailroad into 21 blocks. You could also do this with just two blocks.

If a train crosses over between two power parks and they are set to the same polarity, the train will simply run at the speed of the higher of the two voltages.

If a train crosses over between two power packs and they are set to different polarity, the train will do a "cha cha" back and forth. The few times that this has happened in the last 24 years, I don't think this has ever tripped the circuit breaker.
So by what you're saying, maybe I'm worrying too much about damaging the trackside units and/or locomotives if all it will do is a "cha cha" back and forth with incorrect polarity.

I also failed to mention, both trackside units will be powered by the same 15amp power supply I have. Even running 2-3 locomotives with some lighted cars, I pretty much never see draw any higher than 2-4 amps.
 

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This is an important issue, it led me to abandon my research with using DCS which I did for two years with success. What I did wrong then, is that I came out, when opening the layout after winter, with my F3 A B A set and went over a crossover without having checked the polarity between the inner track and the outer main. The result was that I fried the two boards on both motorised A units. It was stupid of me because all I had to do was to place one A unit on one track and then on the other to see which polarity they were in, but I didn't! The result was a $500 dammage that I refused to pay (having to send the boards to Raymond Manley) + shipping and custom. So that was the end of DCS for me... Now I run in analog mode with a revolution train engeneer.

What to do is actually very simple: My friend Olivier who is much more into electronics than I has made for me four small circuits in a circuit box with leds showing the polarity of the track (respectively Inner or outer) which I will install near the two crossovers of my new pike very shortly, right now I am still working on one power supply receiver and handheld. That way I will have a visual sign of the polarity and can change it before using the crossover.
I run both live steam and electric through track power very often. Unfortunatly they cannot operate together due to the impossibility of insulating live steam locos. I find that mastering electric operations is actually more work than running in steam. provided one knows how to tune ones engines right.
Best, Simon
 

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Discussion Starter · #10 ·
This is an important issue, it led me to abandon my research with using DCS which I did for two years with success. What I did wrong then, is that I came out, when opening the layout after winter, with my F3 A B A set and went over a crossover without having checked the polarity between the inner track and the outer main. The result was that I fried the two boards on both motorised A units. It was stupid of me because all I had to do was to place one A unit on one track and then on the other to see which polarity they were in, but I didn't! The result was a $500 dammage that I refused to pay (having to send the boards to Raymond Manley) + shipping and custom. So that was the end of DCS for me... Now I run in analog mode with a revolution train engeneer.

What to do is actually very simple: My friend Olivier who is much more into electronics than I has made for me four small circuits in a circuit box with leds showing the polarity of the track (respectively Inner or outer) which I will install near the two crossovers of my new pike very shortly, right now I am still working on one power supply receiver and handheld. That way I will have a visual sign of the polarity and can change it before using the crossover.
I run both live steam and electric through track power very often. Unfortunatly they cannot operate together due to the impossibility of insulating live steam locos. I find that mastering electric operations is actually more work than running in steam. provided one knows how to tune ones engines right.
Best, Simon
Your DCS story is the horror that plays out in my mind, and what I think is likely to happen to my locomotive(s) and/or trackside units should polarity be reversed. LED's are a great idea! I've seen it employed before, but didn't really think about it for my application. Thanks for bringing that up as I think it will be a great extra layer of protection to provide a quick visual indication of polarity. And I already have a ton of red/green LED's on hand that would work great for this! This coupled with my DPDT switch setup, as well as being able to "deadrail" the siding I think should be a suitable level of protection to greatly reduce the likelihood of inadvertent crossovers.
 

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I also failed to mention, both trackside units will be powered by the same 15amp power supply I have. Even running 2-3 locomotives with some lighted cars, I pretty much never see draw any higher than 2-4 amps.
Nope! That's a no no. Each TE needs it's own power pack to run a common ground unless the loops are totally separate. Otherwise you will have problems if they crossover with opposite polarity.
 

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Discussion Starter · #12 ·
Nope! That's a no no. Each TE needs it's own power pack to run a common ground unless the loops are totally separate. Otherwise you will have problems if they crossover with opposite polarity.
Do you use the latest version of TE trackside units? Per the above, JK at Precision RC stated they are only designed for single loop control. I'm afraid common ground wiring will interfere with the newer TE units?

I was not planning on using common ground wiring. I'll be isolating both rails across the siding, which will be sandwiched by each loop. Planning on controlling each loop/siding via the crude DPDT switch setup I have sloppily drawn above.
 

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Do you use the latest version of TE trackside units? Per the above, JK at Precision RC stated they are only designed for single loop control. I'm afraid common ground wiring will interfere with the newer TE units?

I was not planning on using common ground wiring. I'll be isolating both rails across the siding, which will be sandwiched by each loop. Planning on controlling each loop/siding via the crude DPDT switch setup I have sloppily drawn above.
Not the latest, but should not make a difference. When they say "single loop" I think they mean that each TE needs its own power source, as I noted,

I don't see why common ground should not work. I run three Train Engineers (on three power pack), an a/c tranformer for effects, two half-wave signals of opposite polarity for the turnouts, and a malibu lighting system for the lighting (eight separate sources) all through the common ground without problem. It saves you almost half the wiring and you use one of the rails as the common wire so it is of very large gauge.
 

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I don't see any reason to try to use a common ground.

Bind each loco to both controllers, and get them on the same loco id.

Wire each controller to each loop, and the "siding" to be able to be powered from either controller.

You should be able to run a loco on loop A, throw the siding to A, drive the train into the siding, then switch the siding to B and continue on B. Done right, you should be able to run the train with the same handheld through this.

Greg
 

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Sorry fellows but as I am still deep in construction of the layout (and paying the bills that goes with it) the two revolution Train engeneers are still in the futur. however I dont plan to use common ground. Just one receiver on one track and another on the other main. The wye should be controlled by my old Aristo train engener as it is close tothe house and there is enough range. I will make two isolated sections between the ends of the wye and the main whith togles to either feed the section with the wye receiver or the mains receiver. Preventing again wrong polarity. This stop will be prototypical as most junctions required a stop and proceed anyways.
Simon
 

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Do you realize that if you have track-lit railcars or run multiple engines, the engine may not stop because these serve as "jumper wires" to the live section?
 

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Super Modulator
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Agreed. I was going to comment when I read the post that the "insulated" sections need to be longer than the longest powered car, which can be pretty long when you think about passenger cars.
 

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Discussion Starter · #18 · (Edited)
Thanks gentlemen. Already conceived of and mentioned in my first post:

There is still a small chance something could "pick the points" and begin crossing over to Loop 2, then act as a conductor and possibly backfeed one trackside unit or the other......" "Other than isolating a larger section of track........ do any of you have any ideas on how I can provide better protection for my locomotives and trackside units should an inadvertent crossover occur?
Unfortunately I do not have any more room to go more to the right and set up an insulated section any longer than what is shown. The shortest section is directly through the crossover (from loop 1, over the siding, straight onto loop 2). I'm going to have to take concessions and deal with the limitations I have. One thing I will do when operating independent loops is run my trains in the opposite direction (for loop 1, the crossover turnout I'll be running trailing point instead of facing point) so the likelihood of an inadvertent crossover will be almost nil. It may still pick the points on the siding turnout since the loop 1 main line will be running point facing and take the diverging route, but that turnout leads to the siding which will be a very long section of dead rail when siding switch is in DPDT center position. I will leave the switch in center position unless I want to move a locomotive on/off of the siding, then return to center position.

For my setup, I think an acceptable level of risk management has been achieved, with the following (thanks to all of you for you help and for checking my blindspots!)
  • Reverse direction operations (as explained above)
  • Additional DPDT to control the siding and "deadrail" it when operating independent loops while not moving trains on/off of it
  • Adding LED's to show polarity of each loop and siding
 
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