Greetings. I just dismantled my layout after 11 years of enjoyment. It was an around the walls with peninsula affair and had a duckunder for continuous run. I found that the duckunder was becoming quite a pain in the back now that I am approaching 60 years of age so I decided it was time for a new layout. The new layout will be an U shape with two return loops and a reverse loop for a paper mill complex. The picture is a simplified version but conveys the general idea of what I am trying to accomplish. My question is in reference to where to place the gaps. Should they go at position A and if so, then the passing siding and spurs are all wired to the auto reverser or at B and only the isolated portion is wired to the auto reverser? I am running DCC with a NCE powercab and a smart booster and plan on using a Digitrax AR1 auto reverser.
Scott
https://www.amazon.ca/photos/share/dy4GuxOJuDTyoX2VaO4RPcqLCpSNE1iEDnYrCxBI2fY
Scott, please try again to post your photo. See the related sticky thread in the General Discussions section. You need to post your photo on a hosting site and insert the right kind of sharing link into your post. I use Flickr, and I copy and paste a "BBCode" link into my post. I'm assuming Amazon Photos will not woirk that way.
EDIT: I got to see your entire photo by logging into my Amazon. You can just put gaps (both rails) at Point A on each track exiting the turnout (the loop side). No reason to make it any more complicated. You could make the reversing portion only the length between your two points "B", but if your longest train can be longer than that, it would be a problem. Do it the simple way (near point A).
You can, as in your case, include any auxilliary trackage that is within your reversing section. The tracks within, a yard or spur for instance, just float electrically with the main part of the reversing loop.
With DCC, a moving loco's decoder knows which way you last told it to move. If a switcher in the yard is moving forward and another train causes the loop to reverse "polarity", the switcher will keep moving forward and seem unaffected. The decoder in the switcher handles the incoming power to automatically keep the motor doing what the decoder was last instructed to do.
The section on Reversing in this website is one I like that covers the various reversing issues:
wiringfordcc.com/track_2.htm#c4
Paul
Modeling HO with a transition era UP bent
If yourt longest trainw ill fit between B and B, you can isolate just that. If not - gap at A and make the whole thing a reverse loop.
Given another poster's issue with shorting a turnout and frying his SB5, I would advise breaking the layout into multiple power blocks with EB1 breakers to power them. This means resorting to a faster solid state reverse loop controller like the PSX-AR, or use a Tam Valley Dual Frog Juicer.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
My vote is to use location A. Only 1 train can occupy the "trigger zone" for the reverser to decide which polarity is correct.
Make sure both departure ends of the switch are isolated.
If you were to use location B as the reversing zone, there is the possibility of a train entering the reverse zone from one end and another train departing the reverse zone at the other end. This situation creates a conflict with the reverser deciding which polarity is correct, resulting in a high probability of the reverser detecting this as a short and shutting off to protect the circuit.
Hello All,
rrinker...gap at A and make the whole thing a reverse loop.
I concur!
Unless you need the siding and spur tracks to be separate power districts I would make the entire loop a "reversed" district.
By making the entire loop a "reverse loop" you eliminate the problem of train length within the loop siding and spur.
Another advantage of making the entire loop a "reversed" district is, the need for a fast-acting polarity shifting A/R unit is not necessary.
Once all motive power is within the loop the reversing unit does not need to "toggle" between polarities during switching duties. Which would make multiple locomotive operation difficult.
Switching commands will be carried out within the "reversed" section the same as the other parts of the pike. "Forward" will still be "Forward".
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Agree, just gap both sides of the switch at A.
There's no problem having two or more trains inside the loop.
There's a problem with two trains or powered cars crossing the gaps at both ends of the loop at the same time. Then you have a dead short that the auto-unit can't correctly. With gaps at A, it's pretty much impossible to do that.
Chris van der Heide
My Algoma Central Railway Modeling Blog
Thanks to all, A it is.