H-0 DCC

[keystone]

It's a new one on me. Just finished laying track for a new layout. I'm using DCC that I've used before. My layout is simple enough to me. Its double track with a return loop at both ends. the return loops themselves are single track. A double track entering the loop by going to single track then meeting the double track again after completing the loop heading other direction. I have crossovers between the double track at one point. Powered the track up and could not get continual juice. (shorted ) I then disconnected the track in 2 spots, Powered up fine. Reconnect track and shorted out. The only tester I have is a DC meter. I put insulated joiners where I had disconnected. Power great on both sides of disconnect now isolated. Tested with my meter, and on one side of the insulated joiner , I have + on left side. The other side of insulated joiner has a - on left side.  I'm afraid to run an engine over this point. Seems in earlier years I had reverse loops and used a reverse loop switch  that had to be thrown while train was in reverse loop. I do not have reverse loops now. Can anyone explain my problem and a solution ? BTW I do use the Bachmann E Z Command and had crossovers on previous layouts with no problems .

[jward]

you do have reverse loops in the plan you described. the crossovers between the parallel tracks is where you run into trouble, without them you'd have a simple dogbone.

any time you can run a train in a forward direction, and go over the same section of track in opposite directions, you have a reversing loop. the easiest thing to do is to use autoreversers on each of the turnback curves.

[keystone]

jward
On my previouis layout I had a crossover from one track to the other where I had double track. Most of the remaining layout was single track with continious running. Never had a problem with the DCC with one wire connection from control. However, I'm aware of old Atlas return loop controls but I don't see a return loop in my present layout. You best describe it as a dogbone. 2 tracks with a loop one North and 1 South. No turnouts. Reading the forums, I gather that DCC has a auto reverser that must be similar to the old Atlas control. I wasn't aware of that. Would 1 or 2 of the reversers correct my problem at the 2 dogbones ? As I was laying track and testing it, the parallel tracks with the crossover , never caused a problem . The problem came at time of final spike. The Reversers I see are computer boards, Can a novice wire and connect them ? Sure thank you for the reply.

[jward]

there are a couple of ways to wire the layout. the easiest is to use an auto reverser on each of the turnback curves. they are pretty simple to wire. you'd gap the rails like you would if you are using the atlas controllers. track power from your command station goes to one set of terminals, similar to using the cab a terminals on the atlas controller. the other set of terminals goes to the track. this is the equivalent of the x-y terminals on the controller.

another way to wire the layout uses only one autoreverser, you'd gap the rails on one of the two parallel straight tracks (the shaft of the dogbone), and use this as your reversing section. whatever section you decide to use as your reversing section must be electrically isolated from the rest of your track. you may want to do a continuity checque before you add any wires to this section. there should be no continuity from any of the rails in this section to anything else on the layout, before it is wired.

you are correct that the autoreversers do automatically what the switches on the atlas controller do. you don't have to worry about flipping direction switches to keep the train moving. the old dc method, using the atlas controllers or toggle switches to control track polarity will still work with dcc, but since the full power output of the dcc command station is available on the rails at all times, a short circuit can have devastating results. and it's easy to forget to flip a switch, and accidentally cause the short.

autoreversers has circuitry which causes them to reverse polarity to the reversing section any time a short is detected. the only thing you have to watch is that you don't have trains longer than your reversing section. locomotives and some cars like lighted passenger cars pick up electricity off all wheels, and span the gap between the reversing section and the rest of the layout. having a locomotive trying to exit the section while one of those lighted cars is trying to enter can burn out the autoreverser as it can't resolve the short.

[keystone]

Thanks Jeffery.   That kind of explains it. So happens, I tested the track in a handy section where it's double track and no way near either of the return loops :)It appears that the auto reverser will work in that area. With the insulated gaps, I found the AC to be 18v Ac on both sides, thus no shorts. now I'm wondering, as I have insulated joints at the same location of the (  Side by side ) double track , Can one Auto reverser handle both tracks ? Wires from one track tied into wires of the other track then to auto reverser ? Chances that 2 trains will pass in that area are almost nil. You've been a great help, I was in over my head .
Joe