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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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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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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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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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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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Discussion Starter #7
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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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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Discussion Starter #9
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
545555
Manager to come home from work at 1:30 am to show me how to post it! Wow! It worked!
 

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Discussion Starter #10
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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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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Discussion Starter #12
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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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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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.
545582
 

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

545602


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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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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Discussion Starter #20
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.
View attachment 545582
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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