Question -Use of of Kato Unitrack Double Crossover with DCC in single track mainline

rogergperkins Jul 14, 2014

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  1. rogergperkins

    rogergperkins TrainBoard Member

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    If the double crossover is used in a track plan for a single mainline are modifications needed if the layout is dcc?
    Running a train on this track plan would continue in the same direction around the loop with the crossover not thrown.
    If the crossover is the thrown, the direction of the train would reverse on the loop.
    Thanks.
     
  2. Carl Sowell

    Carl Sowell TrainBoard Supporter

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    Roger,

    My grey matter is thinning along with the hair on my head or maybe it is just that I too am 74, but I do not understand what you are aiming for. Our club layout has several double crossovers in it and I am having difficulty understanding how throwing the crossover would reverse the direction. Could you post a simple diagram?

    Carl
     
  3. retsignalmtr

    retsignalmtr TrainBoard Member

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    My club uses two kato double crossovers on a couple of our T-Trak modules. The polarity on both tracks is the same with the switches in their normal position (straight). With the switches reversed the same polarity is carried through the diverging route. There is no reversing of any power through the switches in either position. If you use one of these switches with a loop that turns back on itself you would need a reversing loop module like the PSX-AR wired into the loop with both rails at both ends of the loop having insulated rail joiners.
     
  4. rogergperkins

    rogergperkins TrainBoard Member

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    I am approaching age 75, so that is why I am asking this question. It should be quite logical, but I installed DCC and power input on my previous layout by trial and error.
    [​IMG]
    Here is a crude diagram of the right half of the track plan. Another loop will be connected to the left end of the double crossover. Thanks.
     
    Last edited by a moderator: Jul 14, 2014
  5. Doug A.

    Doug A. TrainBoard Supporter

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    You just need an autoreverser, like the Digitrax AR1. There are at least a dozen similar devices out there. Very simple to wire up.
     
  6. rogergperkins

    rogergperkins TrainBoard Member

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    Here is a more complete diagram:

    [​IMG]
    I am using NCE Power Cab, so what is the autoreverser option? Thanks.
     
  7. Carl Sowell

    Carl Sowell TrainBoard Supporter

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    Roger,

    thanks for the schematic of your idea. I can see how you could be reversing so, as Doug has suggested, I think you will need an auto reverser or two. I am not sure but think you will need one on each half of the loop.

    Carl
     
  8. rogergperkins

    rogergperkins TrainBoard Member

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    I had not looked at auto reversers prior to this time and thus do not understand how they are used. I did learn that the one from Digitrax is advertised as being compatible with other dcc systems. As I learn more, it does seem the plan would require two auto reversers, i.e. one for each loop. That still leaves unanswered where insulators would be placed and where the auto reverser lead would be placed. Thanks for the help to this point.
     
  9. DougSluder

    DougSluder TrainBoard Member

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    You can place the insulated joiners anywhere on the loop with one consideration. The distance between insulating joiners must be greater than the longest train you will run. Track power goes to the AR and feeders from the AR to the track inside the insulated joiners. Here is a link to Digitrax instruction for AR:
    http://www.digitrax.com/support/manuals/

    Doug
     
  10. Adrian Wintle

    Adrian Wintle TrainBoard Member

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    One option would be to put the insulators at the end of each of the first track sections after the double crossover. You would then connect the main feed and the track input of each of the two autoreversers to the section with the crossover (you may need multiple main feeds due to the architecture of the crossover). The loop feed from each autoreverser would be connected somewhere on the loop.

    It doesn't really matter where on the loop the autoreversing sections are as long as they are longer than the longest section of the train that can bridge both ends. If you run plastic wheels, this means just longer than the longest loco consist. If you run metal wheels this means longer than the longest train.

    Adrian
     
  11. retsignalmtr

    retsignalmtr TrainBoard Member

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    Over the Winter I wired up a Doctors layout that has a double loop with a double crossover between them. The DCC polarity on the switches was the same for both tracks. Insulated rail joiners were used at all eight rail ends of the switches, and two PSX-ARs were wired into the loops with one for each loop. AR-1s are OK but the PSX-ARs are solid state with no relays. Both typ.es wire in the same way. Each PSX-AR powers the entire loop.
     
  12. atsf_arizona

    atsf_arizona TrainBoard Supporter

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    Roger, I'll second what retsignalmtr said.

    The Digitrax AR-1s are older electromechanical devices, it works fine in most circumstances but there is a chance you might have some edge error "situations" . The PSX-ARs are completely solid state, state of the art, you'll never have any of those "edge situations". Here's one comparison chart: http://www.litchfieldstation.com/xcart/home.php?cat=55 Here's a good forum post: http://cs.trains.com/mrr/f/744/t/225475.aspx Bottom line: Digitrax AR-1 will probably work fine and is cheaper. PSX-AR will absolutely work for sure with no problems and is state of the art.

    Hope that helps!
     
  13. rogergperkins

    rogergperkins TrainBoard Member

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    Hi John, Thanks for the alternative suggestions and hints. I need to do more home work.
     
  14. Point353

    Point353 TrainBoard Member

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    The relevance of that statement is puzzling.
    Was it for an MD, DMD, DDS, DVM, PhD, LLD?
    What is your level of academic achievement?
     
  15. rogergperkins

    rogergperkins TrainBoard Member

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    With the double crossover isolated by insulators from power, how is power supplied to the double crossover?
    Thanks in advance.
     
  16. nd-rails

    nd-rails TrainBoard Member

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    Friends layout has 4x crossovers on dual mainline to add versatility and another on a station/ yard mouth approach on branch. Wiring on main is independent insulated blocks and crossover simply fed via the mains.
     
  17. retsignalmtr

    retsignalmtr TrainBoard Member

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    The relevance of your questions is more puzzling
     
  18. retsignalmtr

    retsignalmtr TrainBoard Member

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    I had to solder the wires directly to the stock rails. You could add short pieces of track to the crossover if you don't want to solder directly to the switches. If you do that you will just have to use the IJ's at the ends of the short pieces of track. The AR units are powered from the same feeders that go to the switches with the AR's output going to their respective loops.
     
  19. rogergperkins

    rogergperkins TrainBoard Member

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    Thanks for explaining that aspect. I like the feeder track section for n-scale, so looks as if 4 of them would be the answer for me.
    Everything is on "hold" here with no viewings of our home after 16 days on the market.
     
  20. StHelenaSteve

    StHelenaSteve TrainBoard Member

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    Hello-
    You can use the 2x to provide the isolation, but it requires cutting the out side rails, as they are continuous.
    That "should" do it, however the factory provided inside rail gaps are not sufficient to prevent electrical contact (shorting) by the metal wheels, which perturbs the AR operation. I painted the rail ends, which worked.
    Other wise, you will need to power feed each "corner" of the 2x, add rail isolators somewhere after each corner of the 2x and add the ARs, as mentioned.
     
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