I have a double reverse loop figure eight with an entry on both ends , any advice on wireing for dcc? i am using Atlas switches
My first question would be: Why? There are probably much better designs for the money and space you have.
But to answer your question, you have to isolate both of your center legs. Then you have to be able to reverse the polarity of the legs with a switch. You can use manual switches or automated ones.
Just get the PSX-AR from Tony’s. You will need one for each of your reverse loops. They have detailed instructions on how to wire it. They are really easy to use, install, and work flawlessly.
Do you have a diagram or pic? A standard figure 8 doesn’t need a reverse loop.
I’m assuming you’ve basically got an oval with a pair of tracks crossing diagonally, right?
Insulate both rails of each of the cross tracks immediately after the turnout when they leave the main line. You don’t need to insulate the crossing. I’d also recommend the PSX-AR. It’s all solid-state and it switches polarity very quickly. It also serves as a circuit breaker to protect the reversing section power.
Strictly speaking, you should have a separate auto-reverser for each reverse section. However, if you will never have a train going through both reverse tracks at the same time, you can get away with one. They aren’t cheap, particularly the good ones, so this is an opportunity to save a bit.
Depending on how long the crossover tracks are and what length of trains you run, you could have a problem. An auto-reverser flips the polarity, if necessary, when the train enters the reverse section. It will then flip it again when the train leaves the reverse section at the other end. If the train is longer than the reversing track, it may be crossing both insulated joints at the same time, which is a situation the auto-reverser can’t resolve. Typically, this will only be a problem if you’re running illuminated passenger cars, which can span the gap for a long time. It may be a problem with any metal-wheeled car, though.
I agree. As I draw a diagram of your layout as you describe it, I don’t see any reverse polarities. A track diagram or photo would help.
Could not have said it better or shorter so I won’t try. I would definitely use one reversing module for each reversing cut off. Lighted cabooses or track powered FREDs could also cause the “long train” problem.