Need advice on N Scale wiring, crossing track and insulated railjoiners.

Milne Jan 26, 2013

  1. Milne

    Milne TrainBoard Supporter

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    After a few years absence, I am back into the hobby. Please excuse what to many may be simple questions, but this DCC is getting a little confusing. Give me a tube amplifier to fix, a horse to shoe no problem, but DCC! (when I was born, the family bought its first TV – black and white). The last time I built a layout was over 25 years ago and it was DC.

    I have read a bit on the net, and there are many different suggestions about wiring etc.. I was at a model railway show recently, and I spoke to an N club representative. He advised that the club does not modify any turnouts and insulated rail joiners are not necessary except for power districts. The club show layout uses both Peco (Electofrog and Insulfrog) and Atlas turnouts.

    I am following an article in MR “How to Build Realistic Reliable Track – Smooth running on N scale track” as a resource for track laying. I am using Atlas flex with Peco Electrofrog turnouts and have a few Insulfrog turnouts as well.

    I am puzzled about when to use insulated rail joiners, and if any turnout modifications are needed. And do I have to modify Peco crossing track? Can anyone, who has done track laying etc., advise me of their experience and what has worked for them. Any other hints you may have would be appreciated. Thanks in advance to those who respond.
    :)
     
  2. jdcolombo

    jdcolombo TrainBoard Member

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    First of all, DCC isn't that complicated from an "electricity" perspective. You are still feeding voltage and current to the track just like with regular DC. There is no "magic" from an electricity standpoint, and no special wiring needed. If your wiring worked well with DC, it will work fine with DCC. Don't let the extra "c" in DCC weird you out.

    Now on to your Peco questions. No turnout modifications are necessary to use Peco electrofrogs or insulfrogs with DCC. That said, Peco electrofrog switches depend upon contact between the point rails and the stock rail to power the frog. Some people like to wire the frogs separately to avoid depending on this point-to-stock-rail contact for power. I used Peco electrofrogs for 20 years without doing this; yes, sometimes I would need to clean the point contact area with some 600-grit sandpaper, but I never had a major issue with power to the frog. For 10 of those 20 years, I used Pecos with DCC, unmodified exactly as they had been installed for DC, and they worked just fine. The one thing you may find is that the gauge between the guard "rail" - it's plastic on a Peco - and the stock rail is wide. This may allow too much lateral movement for correctly-gauged wheels, causing them to derail at the frog. If you have this problem, glue a strip of .010 styrene to the guardrail (if you buy .010 x .060 strips, you just cut the strips to length and glue them on; wider strips will require some trimming flush with the guardrail).

    As for wiring - the rule of thumb with Peco electrofrogs is that you must feed power from the entry end of the turnout, and insulate the frog rails at the exit. In practice, I used insulated joiners on all the exit rails, and used feeders on any rail between turnouts. This system simplifies things if you need to find a short later, and also gives you many options later for deciding on power districts. So imagine a simple loop, with a passing track on one side. You will have two turnouts (a LH and an RH) that will create the passing track. Between the two turnouts, you will have the passing track and the main; then you will have a single track loop that connects the "entry" ends of the two turnouts. If you feed power to any point on the single-track loop, you will be feeding power to the entry point of each turnout (electricity will flow "both ways" from the feed point to the turnouts). Then you insulate all the exit rails of each turnout. This would cause the track between the turnouts to be dead, so you fix this by feeding both the passing track and the main line between the turnouts, and you're done (in practice, you want to use feeders about every 3' of track or so; I typically drop feeders on every section of flex track, which works out to a feeder to every 3' of track or less). You now have 3 electrically-isolated "sections" of your track: the single-track loop and the two turnouts are one section; the passing track is the second; and the main between the two turnouts parallel to the passing track is the third. You can then later decide how you want to group these isolated sections into power districts (if you need to do that); having 3 separate isolated sections also makes it easier to find a short - you simply disconnect power to each section in turn until the short clears, and then you know which section is causing the problem, considerably narrowing your troubleshooting.

    Bottom line: if you just insulate all the exit rails of every turnout and remember to drop feeders somewhere before the entry end of the turnout and to whatever track is coming "out" of the turnout, you will be just fine.

    John C.
     

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