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Reverse Loop Shorting Out

HO enthusiast David G asks readers this:

“I’m DCC – an NCE 5 amp. Am attempting to wire MRC auto reverse module. Loop returns back to main track thru set of points but shorts when points are set to left. Have isolated insulfrog point ends still same prob. One engine has enough weight to run thru without derailing when points straight ahead without derailing. Hookup cars won’t do same.”

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3 Responses to Reverse Loop Shorting Out


    Have you examined your turnout on the bench just by itself? The reversing loop gets its power from the rail that feeds into the rails. These point ends do not need to be isolated. A few feet into the loop at the other ends of the turnout are track insulators on BOTH rails. There is a pair of insulators like this on both the straight and turnout ends of the turnout. The entire train must be inside the loop, that is when the engine crosses the gab, the caboose is inside the other gap . If the frog is insulated, then when checking the ends of the turnouts, each pair of rails is in common with the other branch, same for the other side. I am assuming that when the rails change polarity, the tortoise is getting power as well from the reverser and the it throws at the same time….in the appropriate direction. Again, check the turnout on the bench for proper polarity as the switch throws.

  • Kevin Chingsays:

    I am not sure about MRC but I know the digit track AR1 works with NCE controllers It sounds to me as though you do not have it wired up quite right We wired our up to an insulated section of the track that is able to take a whole lot of the engines in consist if you are running multi loco units.

  • Billsays:

    From everything I have seen and read on reversing loops you are looking for trouble if you run them through a turnout. Best practice is to terminate 6 inches (15 cm) before the turnout. Are you running any other reverse loops on your rail road. If this is the only one is it possible your problem is the booster tolerance time for a short is not long enough. I had that issue with my Digitrax system and fixed in no time with a minor programming change. I am not familiar with NCE systems so don’t know if this could apply to your system.
    Frustrating when these “Miracle Fixes” don’t work but usually is just a small issue we overlooked.
    Good Luck

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