Wiring autoreverse problem

I need some more help with wiring my N scale layout. My configuration is a single track (Unitrack) folded dog-bone with a double crossover. Each loop is separated from the main by insulated joiners on both tracks. I have feeders at each end of the cross-over and I was able to run a train around the loop without a problem as long as I don't throw the turnout.

I then installed an autoreverse board from Tony's Trains at one loop. When I run the train hits the track break at the entrance to the loop the polarity reverses, as I think it should, for the entire run, main and both loops.

I then added a second reversing board for the other loop and when the train hits that one it also reverses polarity and the other reverse board does not change polarity. I believe this is also how it should operate on a single loop of track and indicates that the boards are functioning properly.

Then I engage the crossover and midway through the turnout I get a short indication, in either direction. If I push it through the crossover the train starts again in the correct direction.

Do I need to add feeders and reversing inside the crossover? Do I have the reversing boards in the wrong place? I thought they were to go in the loops according to the diagrams but they are isolated from the cross-over because of the block separations. Any suggestions on fixing or troubleshooting are welcomed.

Thanks

JerryI

 

It sounds like you need to reverse the phase of the feeders on one of the tracks of the double track section.

 

Wiring Autoreverse

Robert, thanks for the suggestion - but I just tried that ( I think) by reversing one of the power feeders going into the crossover and that gave me a dead short all the time. Returning the track to it's original position fixed the short but I still have the problem going through the crossover.

Any other suggestions?

Thanks
Jerryi

 

How long is the main line between the loops? If it's not long enough for the whole train, the two autoreversers could be fighting each other.

Martin Myers

 

Track ength is not the problem Martin, just running an engine for testing and the shortest mainline run from the crossover until it hits a gap for a loop is about 2 1/2 linear feet. The other side of the crossover is about 8 feet on each leg.

 

I have a feeling that is a lesson to be learned myself Dave. The actual loops are gapped on both rails at the start and end of each loop. I also have a yard but that too is gapped at each end and will eventually get an AR board when it goes live.

I will climb back under the table and take a good look at the wiring again and record it this time and then post it. Thanks

 

auto reverse wiring

Dave, I have attached (I think) a pdf file that shows the unfolded dog-bone and wiring. While it does show a third auto-reverse unit for the yard, the yard is not wired yet and has no electrical power.

The program/interchange track is isolated from the layout by gapped track and a dpdt switch. Only three legs from the crossover are wired as shown.

When the engine hits the other side of the crossover it shorts while I thought it should trigger an auto-reverse. I must be doing sonething wrong but don't know what it is.

Thanks for your help.

JerryI

 

Jerry,

There is nothing conceptually wrong with your diagram, so the problem must be something more basic, such as having feeders wired the wrong direction as CSX Robert suggested. Or perhaps something even flukier like a bad gap.

You would need to switch both sets of feeders on one track of the double crossover, not just one.

Or to put it another way, all of the feeders going into the crossover need to be lined up the same way, as if they were double track going in the same direction.

 

Ben, I think I understand what you are saying but not quite sure. I have tried to keep the wiring such that rail A is always on the outside of the loop and rail B on the inside. The track shows no shorts and trains run around it and the two loops without a problem. However when I try to change train direction by running it through the crossover I get a short at the center of the crossover. I also get one or the other PSX board to do a polarity reversal because if the train has enough momentum to ride through the short it continues on OK and the reversal LED indicates the change.

I thought the PSX was supposed to take care of the polarity change fast enough to not trip the breaker in the Command Station. I jumpered the boards for the DCS 50 Zephyr as suggested in the instructions but it didn't help.

I am pretty sure that the center "diamond" on the Unitrack crossover is fully insulated and it does not power feed like the other turnouts do - but I am really new at this stuff and have lots to learn. It is supposed to work, just having a hard time figuring out how to make it happen on my layout.

Thanks

Jerry

 

The two parallel tracks need to be wired the same. Lets call Front the side of the layout where the program track is located.
You want rail A to be the rail on the front side of each track.
Rail B the rear one that's closer to the command station (In your drawing).
That double crossover is built to work between two parallel tracks. If you wire those two tracks like they are in an oval, it will short. They are physically in an oval but not electrically because of the isolated ends and AR's.

Martin Myers

 

Unfortunately, this is wrong. On the section with the double-crossover, the wiring must be parallel. The inside rails must be opposite (an A and a B) and so must the outside rails. Or use Martin's way of putting it (front and back). The advice that Robert, Martin, and myself have given you is correct. You need to reverse the feeders (all of them) on one of the sections running through the double crossover.

Because the two sides of the crossover don't meet up properly. Either the sides have to reverse independently of each other, or they have to be wired in the same direction and never reverse. Given where you are currently at, the easiest way for you to resolve your issue is to make them the same.

If I'm understanding what you're saying correctly, none of this should actually be necessary. If the two sides of the crossover are wired so they meet up properly, then only the two ends of the loops should ever need to reverse polarity.

The idea is that one section of the track reverses fast enough, and subsequently there is no short. In your case, both sections are reversing, and so there is still a short (in the opposite direction, but still a short). Reversing features are designed to eliminate a short by switching polarities so that all tracks match up at the point being crossed by the train. No reversing circuitry is designed to keep a train running through track that can't have its polarity correctly aligned; that would be impossible.

There are indeed gaps in the middle of the diamond. If there weren't, you would experience your short as soon as the turnouts were thrown and not just when the train was present.

 

(Big Bulb lighting up) Martin and Ben thank you . I can see now what you are getting at and I will start swapping wires later today. Since I built a physical loop I wasn't thinking about it as two virtual parallel tracks which the crossover was designed for and when I looked at the wires I was trying to get them all lined up as if it was a single rail line.

Great advice, great forum. Thanks

Jerry