thinking about putting in a wye and was wondering how you revers the polarity? I see that digitrax Ar1 you have to isolate the whole train. Is there any other way?
The whole train has to fit in the reversing section if there are metal wheels.
I'm tempted to say more, but I could be wrong, so I will zip it for now.
Henry
COB Potomac & Northern
Shenandoah Valley
Easiest way? Contacts on the switch machine (or a Snap Relay if you use solenoid switch machines) wired as a reversing switch feeding power to one of the tails. Both rails gapped. When you flip the turnout to go out the opposite track fromt he one you came in on, the polairty flips. No problems.
With DCC you DO flip the polarity of the train. Sure beats changing the polarity of the whole LAYOUT which is how it works with DC.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
You need a switch machine, though, and a two-pole set of contacts. The Peco machines I have are only single pole. I'm not sure if Caboose throws have double or single pole.
It might just be simpler to use an autoreverser.
It takes an iron man to play with a toy iron horse.
Just use the contacts to power a relay with as many contacts as you need - avoid the short instead of fixing it. I believe the same thing should be done for basic reverse loops as well - the obvious type like having a long straight main terminate with a turnout, where the two diverging legs of the turnout loop back on themselves. There's pretty much 0 reason in a case like that to have to wait for a short to flip the polarity, if it's tied to the switch machine then it covers every case - trains with lighted cars, trains without. Train can enter either way and exit the opposite. The only thing that doesn;t work wouldn;t work no matter how you controlled it - a train too long to fully fit inside the loop. Using the contacts/relay means there will never be a situation where one loco/train goes through just fine and another one hesitates because the autoreverse is confused or the upstream power source sees the short faster.
Same kind sof deal with turnout frogs. Sure, Frog Juicers are easy, no thought is needed. But they are also not cheap. Save the fancy self-detecting stuff for the complex arrangements where it truly isn't easy to figure out what the track or frog polarity should be.