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Drum Driver
Ok here's the issue. I am sure this has been covered before. I even read the past post to the link on wiring. Just looking for some personal input. I am new to DCC and am learning the hard way. We started out building a dual mainline which should have basically resembled a double folded dog bone. (easiest way to describe it) The week I wasn't there the guys laid the track near "Chris Creek". Instead of continuing the dual line thru the loops they figured one in the tunnel and one thru the town. With this arrangement it turned the dual mainline into a single track!...So with each trip around its a different track/direction. Which is OK. A couple guys thought when we add the crossovers it wouldn't hurt polarity with DCC. I said it has to. And it did. I had a reversing unit in my stock pile and last night I cut the track into 4 sections (cuts are at bold red marks). We plan on placing 4 reversing modules at these spots... Here's my questions:

1 How many more places do you think we should break it into? (NOTE: dual gauge section from Mt. Union to Rockhill including the "Y" will be a separate analog system.)

2 If train "A" crosses a reversing unit onto next track section, what happens to another train that maybe be in that section?

Am sure these questions prob. seem basic to a lot but like I said I am new to this :( Hope you can see the track ok, track is cut at Chris Creek (on each loop)and directly across from it near blue river.


Fun Lover
The wye will need to reverse polarity DC or DCC.

You cuts seem in the right place. I might have put them closer to the crossovers, but where you did it will work.

In DCC, your trains will run in the direction the throttle says no matter what the polarity of the track. The short happens when the front end of a loco (or lighted car) is on one polarity and the back is on the other.

At my old club, we used toggles to reverse the track instead of auto reversers.


Drum Driver
Thanks Chip! I have the idea down for the Y area, because that's gonna be a separate block ran system since its dual gauge with HOn3. Toggles sound cheaper but allot of attention would have to be paid to watching the flip times (to be ready in time) I bought the reversing unit when DCC 1st came out and I was learning what it could do. I just never applied it to my home layout before it was torn down. I think I paid @ 35.00 for it then, I hope they have came down in price since more companies have gotten into DCC more. Do I need one at each isolation point (4 total,, 2 at Chris Creek and 2 at the river x-ing) or would 2 work at each loop (Chris Creek) correction the whole 4 sections?


DCC Sound Guru
Your reversing loops cuts should be where you know only one train will be at a time....and that train cannot span that loop. So Basically the reversing loop has to accomidate your longest train where only on train will enter the loop at one time. If the loop is shorted at both ends at the same time, you will have a short.

So looking at your picture, your cuts need to be closer together.



Drum Driver
I guess I would want to insulate between the switches at each X-over also since they are 2 back to back switches and once polarity is swapped on one section it won't meet with that section thats still of the opposite. WOW this is about as hard to explain as it is to wire!...Would the reversing unit at say the opposite end of a block be enough to correct it?...What I mean is I don't need a unit at every cut? I could have say a unit....then insulated jointers at next cut, then a unit at the next break?

(( ][=insulated jointer, == track, {unit}= reversing unit.)) Would the unit correct it when the train passes from section 2 to 3?
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What I see is you have crossover from one reversing loop to another reversing loop (Horseshoe Curve). Insulating to the left of the three crossovers on the four tracks will isolate each loop and give you the two reversing sections that are independant of the other. You will need two reversers. One could control both, but not at the same time.

Some info:
The reversing (insulated) section only has to be as long as the loco +, unless you have lighted cars or use resistive axles on any of the rolling stock. If you have a loop only at a length to accommodate a lighted passenger train, then you would only want that train in the loop to prevent the reverser trying to switch back and forth when entering/exiting and/or causing a short. Two engines operating within a very large loop will function normally and independantly even with another entering the loop.

If your design is a wye leading to an ended yard or large area like a town, then a wye only has to be insulated at the beginning of each curved leg. The yard/town can be operated with as many locos as you want at any time and the reversing will not affect them. The same applies to a large reversing loop.

As Chip said, the loco doesn't care what the polarity is. The decoder will sense the polarity and adjust to match the throttle direction. The reversing mechanism, rather an electronic device or toggle, is to prevent the command station from sensing a short on the track.

I have one wye that is at the lead to a large dead ended yard and town area, a wye that has the top (straight) of the wye insulated for locos only at a service area, a loop long enough for a passenger train only, and even a loop/wye combination within a bi-directional town that uses only three insulating points..
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