Reverse Loop Problem

Tom Grassi

Hello All,

Problem is now solved.

I placed an updated doc    AR10 Working     My AR10 now working

I needed to isolate the section of track which had the short circuit.

I had a DCC Feeder wire on that section which was causing the short circuit.
The isolated track section gets it power from the AR10

Check out the document I posted 


Tom Grassi

Tom Grassi


I put a Doc in the files section showing my diagram  I hope that helps better explain

My layout diagram for the reverse loop issue AR10


When I insulated a track both rails have insulated joiners  that is my standard.

Let me know if you need more information

Tom Grassi

Don Weigt

Hi, Tom.

Your description isn't 100% clear. I'm not sure you've gapped both rails of both ends of your reversing section,. That is essential, so if you haven't done so, it is the first step toward a solution..

The only way the reversing track polarity/phase can match the main line at both ends (first at one end, then at the other, not simultaneously) is for both rails in the reversing section (it can be more than one block) to be switched.

If both ends aren't isolated, then for one polarity/phase, the reverser will connect a short directly across the rails. But, it should sense that, and switch back, and the only time you'll be aware of the problem is when a loco crosses the gapped end of the reversing track.

If you have a constant short, then you have a different cause than I described. Perhaps you can send more information to the group.

Don W

Don Weigt

Don Vollrath

Tom. Please tell us what you found
And fixed to help others.


Jim Betz


  Reverse loops are pretty simple - once you understand it.

  Basic premise is that the entire reverse loop is -only- powered via the
reverser.  As in - the reverse loop does not share power with any other
  This sounds like a "reverse loop wiring problem".

  1) Have you double-gapped both legs of the reversing switch where it
      connects to the loop body track?  That's 4 gaps (all 4 rails/two for
      each direction)..
  2) Did you connect the AR-1 to the body of the loop (and not include the
  3) Are you -certain- that there are no other connections to the reverse loop?
  4) Have you checked with a meter to make sure the reverse loop is 
       actually isolated from the rest of the layout?  To check this disconnect
       both power supply wires to the reverse loop - then power up the rest of
       the layout and put the meter between one of the rails of the reverse
       loop and test against both rails of the rest of the layout - should be
       dead.  Test both rails of the reverse loop.
                                                                                   - Jim in the PNW

Tom Grassi



Hope all is well


I have a simple setup here.


I have one track Black wire on inside rail and red wire on outside rail    that connects to a right hand Atlas Powered frog turnout.


The diverging track has the opposite black and red wires so I get a short circuit.


I have an NCE AR10 and that did not work same problem


So I have a TAM Valley Mono Frog Juicer MFJ


I have a green wire on the frog connected to the middle contact on the MFJ


I have a red and black wire on the outer contacts on the MFJ


I have them alligator clipped onto the track


I tried on the main line and flipped them


I tried on the diverging track and flipped them


Still short circuit the track


I tested the frog I do have power on the on the frog.


The diverging track has insulated joiners

I have an NCE AR10 and that did not work same problem

The wiring is simple   three wires on the Mono Frog Juicer
Four wires on the NCE AR10  the frog wire is connected to a tortoise machine when I use the AR10  but when I try the MFJ the frog wire connects to the MFJ

That's really the only difference

I really do not believe I have two bad boards. but its possible.

Any ideas or suggestions.

Tom Grassi