Hello everyone, I am stuck and need some help. This is my first layout with a double crossover in a basic dogbone design. The crossover is Walthers #948-83051 (DCC Friendly). I use two NCE AR10s to isolate the dogbone loops. I followed the wiring guide from this website wiringfordcc.com/track_2.htm. but I am still doing something wrong.
My problem is all my locomotives cause a short when entering the cross section but runs fine going straight through. I know that the polarity is different through the crossover but I thought the AR10’s would fix this. The short is so bad that the entire NCE system will reboot. I push the locomotive through the crossover and increase the throttle again and it will run fine until it enters the cross section and does the same thing by shorting out. All the switches including the crossover are manual throw. Not sure if this helps but all the other turnouts are Peco snap switches.
A picture of my track plan is below. The yellow lines represent where my isolators are, and the R/B is the color of the feeders and are shown roughly where they are on the layout. Everything below the yellow (East and West loops) are using its own AR10 and wired accordingly but they never trip or reverse, according to the light on the AR10. The crossover section at the top is wired to the main bus wires with no AR device. I am at a lost on how to fix this short and any help will be greatly appreciated.
Apart from a crossed wire, which sounds essentially impossible if you can use the outer main without polarity conflict, then the trouble must be where you have the gaps. The legs to the gaps seem long to me, perhaps unnecessarily. You really only need to reverse the crossing itself (only one train can use it at a time when crossing over) and the junction at the right hand loop which is much closer than your two gaps at right.
Have you staggered the gaps transversely where you have them? That can solve problems as well if two metal tires bridge gaps at the same time.
You have to rewire that middle section between the reverse loops so that the polarity is the same on all the tracks on either side of (and including) the crossover.
On the upper left of your diagram, you have R on the outside rail and B on the inside (which I assume is meant to show positive and negative polarity). Follow the line to the right and thru the crossover to the inner track. Now B is on the outside rail and R is on the inside rail. That’s a short! Engines can go straight with no problem, but when they go through the crossover, they’re hitting reverse polarity.
You have to change the wire connections on the tracks between the reverse loop so they’re all R on one side and B on the other.
You have correctly wired the dog bone by isolating the two end loops, but when you do that and have a (double) crossover in the non-reversing sections of track, the polarity of the entire non-reversing sections of track must match (in phase).
In your current situation, the straight through routes on the double crossover work without shorting just as if you had one large loop of track without the double crossover. But take the divergent routes and you wind up with a short due to opposite polarities.
Also, be certain that the bottom half of the double crossover is wired the same way as the top of the double crossover, red over black, to avoid shorting on the divergent routes. Right now, the shorting occurs in the middle of the double crossover where opposite polarities meet.
Big thanks to selector, wjstix, and richhotrain! Swapping the feeder wires just like you suggested solved the issue perfectly. I really appreciate the guidance—couldn’t have done it without you. You guys are the best!!
Thanks,
Brian
