Am putting together a 2rail RR with essentially two seperate loops and two single cross overs with two totally separate power sources & two separate TIU.
Trains to run in prototypically opposite directions but will need to smoothly cross over to the other loop to access yard and terminals.
If I correctly polarize each right of way to be DCS PS2 directional compliant how is DCS PS 2 handled at single or double cross overs where conflict will occure?
I am sure I am missing something.
Thank you.
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There are a couple of ways to attack this.
You can set both lines with the polarity matching, then set the switches on the PS2 locomotives to reverse polarity for the ones going opposite of normal (right-hand positive). You'd have to run on AC track power.
The other way is to wire the layout as it was if it was a DC conventional layout with mechanical (i.e., switches or relays) polarity reversing. That way, you don't have to change the polarity switches on any of the locomotives, but you'd have to be mindful of the polarity when you hit the crossover and the subsequent tracks leading to the yard.
When I was investigating building a 2-rail DCS setup, I looked into mechanical-style polarity equipment from Azatrax (http://www.azatrax.com) to handle reverse loops.
Hope this helps.
Matt, Thank you.
This layout is wired for dual control. DC and DCS using 9 MTH DCS 12 & 24 circuit terminal blocks with each one being fed thru a d.p.d.t. and each star run is a dedicated 12 ga twisted feed with it's own toggle.
BTW, we ran out of MTH terminal blocks and found that Miller Signs has a pretty good substitute.
Going to check out azatrax.....................
Matt, Thank you.
This layout is wired for dual control. DC and DCS using 9 MTH DCS 12 & 24 circuit terminal blocks with each one being fed thru a d.p.d.t. and each star run is a dedicated 12 ga twisted feed with it's own toggle.
BTW, we ran out of MTH terminal blocks and found that Miller Signs has a pretty good substitute.
Going to check out azatrax.....................
You can also use the Miniatronics terminal block. It's virtually identical to the MTH version.
While the Proto-2/DCS polarity issue bothered me (DCC doesn't care about such things) it made me immediately think of all of those 2-rail DC layouts and how they handled 2-way operation. Simple: set polarity at the block level. I just applied that theory to DCS configuration. Sometimes the answer to a problem lies in our [sometimes sordid] history. 
Make sure the x-overs are isolated properly and it won't be a big deal. Maybe I'm missing something here again.
Those frogs on the crossovers will either have to be switched for polarity and wired as Matt describes, or just cut them short enough for the engines to cross over and leave them dead, right????
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