# Reverse Non-Loop



## Trucker Sam (Jun 9, 2019)

I have an N scale DCC layout that I’m building. I have 2 (two) reverse loops that ARE NOT LOOPS. One is 5 feet long and the other is 16 feet long. All videos show how to wire a loop. Google has not shown me a video where the person wires a non-loop. Any help, please?


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## Stumpy (Mar 19, 2013)

I don't understand. Are you talking about a wye?


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## CTValleyRR (Jul 26, 2014)

I'm with Stumpy -- I'm stumped. It's either a loop, or it isn't. If you have a situation where a train can leave a turnout on one leg, and return to the other leg heading in the opposite direction, you have a reverse loop, regardless of the actual track configuration that creates it.

Post a track diagram, or at least a photo that shows the entire layout, and we can help with this.


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## cv_acr (Oct 28, 2011)

Trucker Sam said:


> All videos show how to wire a loop. Google has not shown me a video where the person wires a non-loop. Any help, please?


Don't get hung up on the word "loop". Any reversing section is wired the same, whether it's a standalone loop or a track that forms a reversing connection connecting a twisted or pretzeled track arrangments.


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## mesenteria (Oct 29, 2015)

Gap the non-loop reversible length of tracks at each end. Feed that length separately with its own isolated pair of feeders. Control phase/polarity via a DPDT toggle or an auto-reverser that, in turn, gets its power from the bus or main controller's outputs.


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## DonR (Oct 18, 2012)

You have a 'reverse loop' when you can turn a loco around and return
on the track it came in on.

You say you don't have a loop. The only alternative is a WYE...it looks just
like the letter Y with a track across the top. A train enters, for example, thru
a turnout at the bottom of the Y then into the RIGHT 'LEG' of the Y and proceeds thru a 2nd turnout
at the top right of the Y until the train is clear of it. The 2nd turnout
points change and the train BACKS across
the Y until it clears the 3rd turnout. Those points change and the train moves
forward thru the 1st turnout (it's points have changed) and proceeds back on
the track it came in on...

...You have two or three choices as to which section is isolated depending
on your layout. For example, you could install insulated joiners between 
turnout 2 and the track across the Y. You would also install insulated
joiners between turnout 3 and turnout 1. You would use a reverse loop
controller to power this isolated section. All track and turnouts outside of
this isolated section would be powered the same as the rest of the layout.

To give you more exact directions you would need to post a drawing of
your layout that includes the 2 'WYES' you mention.

Don


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## Trucker Sam (Jun 9, 2019)

cv_acr said:


> Don't get hung up on the word "loop". Any reversing section is wired the same, whether it's a standalone loop or a track that forms a reversing connection connecting a twisted or pretzeled track arrangments.


They always say that to reverse the power, you have to enter the section with all your train, THEN switch the switch. If the other end is already open, how does the reverse module know to switch polarity?


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## DonR (Oct 18, 2012)

Sam

Here's a quick refresher on how an automatic Reverse loop controller works:

When the front wheels of a loco spans the insulated joiners going
into the isolated section there is a momentary 'short circuit'. The reverse loop
controller reacts in microseconds and matches the iso track to the main track
and the loco continues without pause...when it then reaches the opposite end
of the isolated section, the loco wheels again 'short', the controller again
matches the iso section to the main track and the loco continues on it's way.

Now as to your question regarding whether the whole train must be in
the iso section...it isn't necessary UNLESS you have lighted cars...a train of those
MUST ALL be in the iso section...which is why we say that your isolated
section must be longer than the longest lighted train.

Now, since you indicate that your 'reverse loops' are WYEs it would
be necessary, of course, for your whole train to have cleared the turnout
at the top left arm of the Y (per my previous example). Having cleared
that turnout the train is out of the iso section. The length of the track
that runs right of the #2 turnout and the length of the track to the left
of your #3 turnout would limit the length of your train...again per my
earlier example. That being the case there could NOT be any car
on the 'entry' point AND the 'exit' point to cause 'confusion' of your
reverse loop controller. 

You are aware that if you have two such 'wyes' you must have a
separate controller for each.

Again, we are still 'flying blind' since we do not know your exact
track layout...if you could make a simple drawing take a pic of
it and post that here we could better be able to help you.

Don


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## Trucker Sam (Jun 9, 2019)

Thanks for the explanation. No, they are not wyes. I call them non-loops because they have an entry switch and an exit switch. I drew up a simplified track plan but need the Division







Manager to come home from work at 1:30 am to show me how to post it! Wow! It worked!


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## Trucker Sam (Jun 9, 2019)

The only thing I have to make it too long is a ATSF Super Chief with lit Obsv. Car. I’m told I can convert it with a battery powered interior, because I do like seeing the lit Drumhead. None of the other cars have lights. Just haven’t found the conversion kit...


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## Shdwdrgn (Dec 23, 2014)

You actually have at least three potential reverse-loops there, but I _think_ you can wire the top curve on each side as an individual loop and protect against the possible ways a train can reverse its polarity. And yes, from the way you've drawn it you absolutely have the common definition of reverse loops there.


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## Trucker Sam (Jun 9, 2019)

This is a very simplified drawing of the layout. The top two curves are not part of the reverse loop. There is a bunch of track not drawn to keep things simple. The tracks in question are labeled “Rev Loop”. And sorry, but no they are not the common definition of reverse loops. Every reverse loop I have seen has ONE switch that has one track leading from it and to it.


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## gregc (Apr 25, 2015)

Trucker Sam said:


> Every reverse loop I have seen has ONE switch that has one track leading from it and to it.


reverse loops can be more complicated than that


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## T-Man (May 16, 2008)

Your reverse sections go from switch to switch. You have two sections one for each side. If you enter one, the track polarity will have to change before it exits. When it does depending on which you use , the direction will change clockwise or counter clockwise. The hint to find them is you enter it to switch direction when you exit and you cannot go through it again using that rotation ( placing the engine in reverse). You have to reverse direction again before you can enter that first switch.

The first switches are the farthest left and right. Both sides travel down to the switch. The left turns left to reverse direction. The right turns right to reverse. These sections need to be isolated to the next switch .

Travel clockwise take the right switch to reverse. and take the left switch when traveling counter clockwise to reverse direction.

Notice I did not say loop once, but when you get to the point that track polarity has to change to keep going forward the loop ends.


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## J.Albert1949 (Feb 3, 2018)

*OP:

The "rev loops" that you had specified above ARE NOT REVERSING LOOPS.*

I have made some annotations to your plan below.
The track "in green" is your "MAINLINE" -- you can run continuously around it without problems.

You actually have *TWO* "reversing sections".
Running a train through EITHER of them will result in a short, unless you insulate the rails (show in red lines below), and use either DPDT switches or with dcc, use an auto reverser. I don't use any auto reversers, so I don't know if one or if TWO will be needed for two reversing sections.

One reversing section is indicated in blue below.
The other reversing section is in orange.

The orange one looks long enough to hold an entire train.
The blue one, perhaps not.
Chances are, it will work ok, anyway. You'll have to try it to see.


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## DonR (Oct 18, 2012)

Sam

You have come up with a real doozie of a layout. The suggestions
of our members are quite correct...but there is more than one
way to skin this cat.

I drew your track plan out using red for right rail and black for left
rail. I also 'toyed' with the idea of the basic oval as shown in
green by J Albert. However, it did create two sections that
we refer to as 'reverse loops'. The 'blue' section is quite short which would
preclude long trains thru it. However, I see that we can make the entire
right loop and connecting tracks as one isolated section which
would accomodate long trains. Here is how I would place
insulated joiners to accomplish this.

I have labeled the four turnouts in your drawing as follows:

A Left most at bottom of left loop
B Right side of left loop
C Right side of Right loop
D Bottom middle where you are connecting the two loops.

Place insulated joiners between turnout B and the right loop track.
Place insulated joiners between turnout B and turnout D.
Place insulated joiners between turnout C and the 'shunt track'
across the bottom.
Place Insulated joiners between turnout D and the left loop.

I understand that you have provided a 'simplified' drawing and
that there are other tracks connected. All of those connected
to ONLY the right loop isolated section would take the
auto reverse power and would not be insulated from it.
All of those connected OUTSIDE of the
isolated section would take the main power feed.

Any not shown that connect to BOTH the isolated section
and the rest of the layout would have to be identified. They
may change the whole scheme presented here.

You would power the isolated section with one reverse loop
controller.

A word of caution. There are three 'portals' to the isolated
section above. If more than one train 'entered' any of
the 'portals' at the same time the reverser could be conflicted and likely
would result in a 'short circuit' shutdown. So you would
want to control your trains to avoid this.

Don


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## mesenteria (Oct 29, 2015)

Or simply wire in-series two reversers, one for each length of gapped, reversible, and potentially conflicted, tracks. The analysis of your plan by J.Albert1949 is right on the money. 

Technically, you COULD use only one AR to deconflict both track segments, perhaps even simultaneously, but as pointed out by Don, above, you'd have to be careful not to allow two metal tires from two different trains to cross the conflicting gaps simultaneously. In fact, the chances of you failing to keep them sufficiently separated in time is about 99% on at least one occasion. Hence, my advice in my first statement just above; two different reversers, each responsible for managing its own segment of gapped rails.


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## Mark VerMurlen (Aug 15, 2015)

Don, is this what you had in mind for an alternative?










Not sure if I followed your description properly or not. I think this would work too and really only has 2 entrances to the single reversing section in blue. Like you say, if there's more track involved, it might make this less desirable.


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## DonR (Oct 18, 2012)

Mark

inre: your latest drawing.

Almost....in my scheme, the long 'rev sec' across the bottom should be blue making
it a part of the main track power. All the rest you show in green would be the
isolated section powered by the reverse controller. There would be NO insulated
joiner connecting it to turnout A, but would require insulated joiners where it
connects to turnout C.

Your scheme would also work well. It has the needed long iso section, but, like
my scheme, it also has FOUR entrances to the iso section, 2 at turnout A and 2
at turnout B.

Sam

You've got some good ideas to make your layout
work. What do you think?

Don


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## Trucker Sam (Jun 9, 2019)

J.Albert1949 said:


> *OP:
> 
> The "rev loops" that you had specified above ARE NOT REVERSING LOOPS.*
> 
> ...


Thanks for your help, but. Yes, my two labeled reverse sections ARE reverse sections because I added them to the plan I “borrowed” which didn’t have any. I don’t have a problem with the blues and orange sections IF. The bottom section next to the 10’ sign is a double track part of the way, with a stub siding. This track was designed to be not only a rev loop but also partly hidden and a place to park my passenger train so it could run as a later return trip.


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## Trucker Sam (Jun 9, 2019)

Trucker Sam said:


> Thanks for your help, but. Yes, my two labeled reverse sections ARE reverse sections because I added them to the plan I “borrowed” which didn’t have any. I don’t have a problem with the blues and orange sections IF. The bottom section next to the 10’ sign is a double track part of the way, with a stub siding. This track was designed to be not only a rev loop but also partly hidden and a place to park my passenger train so it could run as a later return trip.


Sorry, had to post before I was done. Now where was I? Oh, yeah. What happens if I leave the Passenger train on one of the double main of the bottom rev. section hidden track? Also, the orange track has a Industrial complex switch right where the bridge crosses the main. Problem? And I have 90 percent of the track drop lines installed. Do they wire to the main bus normally if they are in a reverse section?


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## DonR (Oct 18, 2012)

Your main DCC controller will power the bus for ALL of your
non 'isolated' track. It will also be the input to the reverse
controller. In my scheme all Isolated track will be powered by the Reverse
controller. So, you may have to change some drops from
main bus to reverse controller bus depending on what
track section they are connected to.

Any tracks connected to main non isolated sections will
be powered by the main DCC bus. Any tracks connected to
the isolated section will be powered by the reverse controller bus.
Since you are operating DCC you may park your passenger
train wherever you want...it won't matter if it's on the main or
an isolated section. It won't be affected by the reverse
controller switching phase. That's just one of the great things
about DCC.

Don


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## mesenteria (Oct 29, 2015)

The entire layout is powered via a square wave digitized signal-carrying voltage and amperage. All the reverser does is correct phase conflicts. It doesn't impart its own digital signal for the decoders inside the locomotives to interpret...it merely passes on what the main DCC controller imparts in the way of controlling signals, but now without a phase conflict across the gap where the locomotive or first car entering the controlled section is. 

So, this is why the reverser is wired in series into the wiring plan. It only corrects phase for one small length of rails, but it still puts through the same signals instructing decoders all over the layout if you have several locomotives on powered rails. When you consider its purpose and placement that way, figuring out how to wire it into place becomes much easier.


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## Trucker Sam (Jun 9, 2019)




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## Trucker Sam (Jun 9, 2019)

mesenteria said:


> The entire layout is powered via a square wave digitized signal-carrying voltage and amperage. All the reverser does is correct phase conflicts. It doesn't impart its own digital signal for the decoders inside the locomotives to interpret...it merely passes on what the main DCC controller imparts in the way of controlling signals, but now without a phase conflict across the gap where the locomotive or first car entering the controlled section is.
> 
> So, this is why the reverser is wired in series into the wiring plan. It only corrects phase for one small length of rails, but it still puts through the same signals instructing decoders all over the layout if you have several locomotives on powered rails. When you consider its purpose and placement that way, figuring out how to wire it into place becomes much easier.


Check out the new and improved graphics


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## DonR (Oct 18, 2012)

I see the additional tracks and spurs but they don't change anything
from the scheme I've posted before.

Don


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## Trucker Sam (Jun 9, 2019)

J.Albert1949 said:


> *OP:
> 
> The "rev loops" that you had specified above ARE NOT REVERSING LOOPS.*
> 
> ...


The reason that the orange line won’t work is that to simplify things I left out that what you have as the orange line is in fact a double main. And it stars “north” of there just opposite the “To Yard” sign. Please refer to new map above. Also, I’m confused about how to power the Reverse sections. Somewhere today I read that it’s different from power coming from the Main Bus. Sorry, wasn’t trying to confuse you guys, but I wanted to keep the map simple.


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## DonR (Oct 18, 2012)

Sam

You may have been confused by the terms used. The 'reverse' section
takes it's power from the reverse loop controller. The reverse controller
takes it's power from the main DCC controller bus that powers the
non reverse tracks.

Stay with us, it's easy to get confused
by different terms.

I am confused by your post that discusses additional tracks. I can't
match your words to the drawing.

Perhaps a whole new drawing showing the 'new' tracks you mention.


Don


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## AmFlyer (Mar 16, 2012)

This is a simple but nice track plan. There are multiple ways to wire it, I thing the easiest way that works with any combination of trains operating is the following. Wire the green highlighted track directly to the power supply. Wire the red highlighted track between turnouts A and D, including the double track and siding, through a reverse loop controller (PSX-AR). Wire the red highlighted track between turnouts C and D through a second reverse loop controller. That reverse loop looks too short to me. The easiest fix to lengthen it is to remove the insulated gaps in the diverging leg of turnout D and put them in the straight leg. Then put insulating gaps near the bridge. This makes the orange part longer but has part of the main line connected to the reverse loop controller. The trains and controller will not care, the layout will run fine. If the train is just running on the main line the controller will never actuate. It will only actuate when C and D are set to the diverging route.
The Turn Table shown also needs to be wired through its own reverse loop controller.


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## CTValleyRR (Jul 26, 2014)

DonR said:


> I am confused by your post that discusses additional tracks. I can't
> match your words to the drawing.
> 
> Perhaps a whole new drawing showing the 'new' tracks you mention.
> ...


Don's right, here. In the effort to keep things simple, you're actually adding to the confusion. A full track diagram, with all the spurs and parallel tracks carefully drawn in, will help us give you the best advice possible. Otherwise, you'll keep getting advice to which your response will be, "that won't work, because things REALLY look like this."


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## Trucker Sam (Jun 9, 2019)

AmFlyer said:


> This is a simple but nice track plan. There are multiple ways to wire it, I thing the easiest way that works with any combination of trains operating is the following. Wire the green highlighted track directly to the power supply. Wire the red highlighted track between turnouts A and D, including the double track and siding, through a reverse loop controller (PSX-AR). Wire the red highlighted track between turnouts C and D through a second reverse loop controller. That reverse loop looks too short to me. The easiest fix to lengthen it is to remove the insulated gaps in the diverging leg of turnout D and put them in the straight leg. Then put insulating gaps near the bridge. This makes the orange part longer but has part of the main line connected to the reverse loop controller. The trains and controller will not care, the layout will run fine. If the train is just running on the main line the controller will never actuate. It will only actuate when C and D are set to the diverging route.
> The Turn Table shown also needs to be wired through its own reverse loop controller.


Good straight forward advice. My only question is the “every track section must have a drop wire to the bus” practice. On the reverse sections, especially between switch A and B, do I tap into the wires coming from the reverse Module to the reverse section to power additional track sections? Am using Peco c80 Flex.


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## AmFlyer (Mar 16, 2012)

The answer to that question is yes. On my layout all the track joints are soldered, a lot of work. Because of the soldered joints I have a power feed connection on every other section of flex.
The other way to lengthen the reverse loop I did not mention is to just move turnout C up closer to the TT area. I thought it would be a lot more work if that part is already built and also it might interfere with the yard area.


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## AmFlyer (Mar 16, 2012)

Here is a simplistic but clear track wiring diagram. The power from the power supply is on the terminal strip on the left. If there is more than one power feed required to the track sections powered through the PSX-AR it is easiest to take the two output wires From the PSX-AR to a separate terminal strip then run wires from there to the multiple track sections.


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## Trucker Sam (Jun 9, 2019)

AmFlyer said:


> The answer to that question is yes. On my layout all the track joints are soldered, a lot of work. Because of the soldered joints I have a power feed connection on every other section of flex.
> The other way to lengthen the reverse loop I did not mention is to just move turnout C up closer to the TT area. I thought it would be a lot more work if that part is already built and also it might interfere with the yard area.


To quote “Young Frankenstein“, IT WOULD WORK! Yes, all the track shown is already built. But as you already said, it hurts nothing to extend the reverse section into the Main. Just have to measure that darn (beautiful) Passenger train! Keep fingers crossed, I’m heading down to the dungeon, time to work. Wife said this morning “I’d like to see something run BEFORE I die!” No, she’s not sick... Well maybe in the head, look who she married. Thanks to all for your help. Sam


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