Newbee Wiring Questions

Discussion in 'HO Scale Model Trains' started by davidzog, Jan 25, 2007.

  1. davidzog

    davidzog New Member

    Hi...this is my first post and I am working on my first layout. It is a 4x8 and I am planning an oval inside an oval with a crossover....hope that is correct. the plan is that the rtrain will run the outside oval and cross to the inside oval, then back to the outside oval. I would also like to run two switches from the inside oval to terminal ends for storage of extra car, and some camping scenery, etc.

    I am toroughly confused with the wiring. DO I need to wire each loop on a seperate power pack, or will one hookup for a single power pack do the job for both ovals? I guess you can tell I need help...

    Also, do I need to wire the turn outs seperately??? HELP?!??!

    I have looked at alot of books and manuals and iinternet sources, but they always assume you know what is going on in advance...I honestly do not get it...sorry...thanks in advance
  2. Tomytuna

    Tomytuna New Member

    Hi david! answer your question you need to answer a couple of questions. #1 are you using the old tried and true DC ( analog) type that uses a single transformer or are you using DCC ( the modern ) type system which controls engine one at a time? Once you let people know which type you are using you will probabaly get a lot of help here..regards Tom
  3. davidzog

    davidzog New Member

    Hi Tom...thanks for the response.

    SInce I had no idea what DCC was, I had to look it up before I could, as you might guess, I am using the old DC system that came with my train set...

    The DCC sounds great, but I need to get started with something simpler for a little while...thanks again...
  4. Russ Bellinis

    Russ Bellinis Active Member

    If you are only runniing one train, you can run one power pack and wire both ovals to the same power pack.
  5. Santa Fe Jack

    Santa Fe Jack Member

    Have you read the very similar thread entitled "2 trains /w DC"? That should answer most of your questions.

    First off, running an oval within an oval is tight in a 4x8, but it will work.

    If you are running only one engine, then your wiring is simple - just hook up all track to the same controller. You can add wires at any place, and probably want at a minimum a terminal on each oval.

    However, if you like the idea of running one engine around the outer oval while having another work independely on the inner oval, either running around (even the other way) or working the yard, then the two ovals will need to be isolated and attached to separate controllers with separate wire runs.

    The isolation is done at the crossover, as you suspected. How to do this depends on how you intend to construct your crossover. If you want to be able to cross over from outer to inner, as well as inner to outer, you will have, in effect, two crossovers. This can be done with four separate turnouts, arranged in pairs, or it can be done with a fancy piece called a double crossover, where the two crossovers actually cross each other in one track piece. In essence, it is four turnouts in one.

    If you opt for the four separate turnouts in pairs, insert the insulating plastic track joiner between the two turnouts, where they meet.

    If you go for the double crossover, it will probably already be electrically isolated.

    You will not need to wire the turnsouts or double crossover separately.

    Does this help?
  6. DRail

    DRail New Member

    Hi David,
    As long as you have just one train running around, you can wire all your track with one power pack. Simply check that all the rail joiners are in place to ensure that the whole layout is powered. If you want, you can add extra wiring here and there to make sure that the engine gets its power all around your layout, but all wires can connect to the same power pack.
    Just look at it as follows: One rail is +, while the other is -. As long as you wire up the + with the +, and the - with the -, you'll be OK.
    Hope this helps...
  7. davidzog

    davidzog New Member

    Wow...this all helps a whole lot...thanks so very much. It gives me a lot of options I had not thought about. SomehowI have wound up with two power packs, and that apparently gives me a lot of versatility that I did not know I had.

    Thanks again!!:)
  8. green_elite_cab

    green_elite_cab Keep It Moving!

    DCC is actually simpler than DC, although much more expensive. with DCC you don't need to hurry up and through toggles to change track power. its definitely worth it.

    running 2 trains on DC is easy. Its known as block wiring.

    first you need to divide you track plan into secontions in which a train might be running indepently of another. these sections will be electrically blocked from one another on atleast one rail. You must block the same rail consistently throughout the layout. the other rail will be left connected as the common rail. it makes sense! just use insulated rail joiners on the outside rail of each oval at every spot in which one block ends and another begins.

    now you need to get power to each of the insulated blocks. you should install a feeder rail joiner ( a rail joiner with a wire) in between insulated rail joiners. drill a whole through the table and road bed and string the wires through. you will only need one feeder rail joiner for the common rail, since it is not insulated

    next you need atlas selectors. on the selector, there will be 2 terminals on each side. on the top, there will be 4 terminals.

    you will connect one of the feeder wires from the track to a corresponding terminal on the top of the selector, and you will connect each feeder to a terminal on the top. leave the common rail feeder alone for now. now, the other 2 terminals are for the different power packs, or cabs. you will take your first dc power pack, and wire the upper DC terminal to the cab A terminal, and you will take the other DC powere pack, and attach the upper DC terminal to the Cab B terminal.

    finally, you will wire the common rail feeder to the lower DC terminals of both power packs. It should all work now.

    in order to control a train with Cab A, move the selector switch up. this will cause the track in the corresponding block to be controlled by your first DC power pack. to control a another train, you slide that switch down, so that it will be with Cab B.

    NEVER LET 2 TRAINS FROM A DIFFERENT CAB ENTER THE SAME BLOCK. this will short circuit the layout.

    here is a diagram. note that it has 2 common rail feeders because the outer oval is not connected. since you have crossovers, you only need one.
  9. Santa Fe Jack

    Santa Fe Jack Member


    Is it better to wire with a common rail, or does it work just as well to wire each block with its own + and - wires?

    Why is the common rail approach better? Just because it uses fewer wires? Or are there other reasons?
  10. green_elite_cab

    green_elite_cab Keep It Moving!

    well basically, its electrically redundant to block off the other rail.

    you just need to regulate how and which way the power flows into your trains (which it can be either rail as long as you stay uniform with it. it doesn't matter which way it flows out as long as it goes back to the power packs.

    and yes, it is also less work and money involved.

    the only time you'll need to block both rails are in places where the common rail would meet up with the blocked rail ( IE a wye, or a turnaround). Special wiring is required in this situation.
  11. Santa Fe Jack

    Santa Fe Jack Member

    But - please forgive my electrical naivete (really inexcusable for an engineer :oops: ) - but what happens if I reverse the polarity on one block, as in making the engine go the other way. Doesn't this cause problems in the common rail approach?
  12. green_elite_cab

    green_elite_cab Keep It Moving!

    nope. I forget why it works ( i used to know a whole lot more about electronics. but if you don't keep at it, you forget it) but basically it doesn't matter. as long as everything matches like it's supposed to, there should be no problem.
  13. cidchase

    cidchase Active Member

    The DC terminals on a power pack reference only themselves, with no connection to
    either ground or the AC side.

    When one DC terminal on each power pack are connected and tied to the common rail,
    that whole side can be considered at zero volts. The other terminal on each pack will
    show either negative or positive voltage when measured to the common side, depending
    on the setting of the direction switch on that pack.

    The + and - are not absolute quantities, only referenced to the other terminal.

    Prolly clear as mud, I can get some kind of sketch up if anyone wants. The Atlas wiring
    and layout books show the common rail method of wiring.
  14. 60103

    60103 Pooh Bah

    Re: Common rail wiring.
    If you have 2 separate power packs, you can connect one terminal each together and have no problems. If you connect both you will have interesting times when you change one reversing switch.
    If you have a series of lines each with its own power pack, having one rail common will let you run smoothly from one oval to the other even if you have those locos where the pickup is staggered -- one side on the loco, other on the tender. For these locos, if you don't have a common rail the loco will stop when it's picking up from 2 different packs.
    The main advantage of common rail is less wiring -- only half as many wires go to the control panel and you can get away with simpler switches.
  15. Santa Fe Jack

    Santa Fe Jack Member

    Well, that settles it, then. That means that my overly ambitious plan of four controllers on 11 blocks can happen using a 6TDP (or is it 6PDT? -- it switches two things at a time, selecting one of 6 circuits) rotary switch, and it give me enough to run the tracks on one pole and use the other for lighting the colored lights for each block to identify which controller is is charge (red/green/blue/yellow or none).

    Very good. I think I see a path forward.

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