sorry to say-- no pics!

What kind of loop?  is there a reversing loop?

With the exception of a reversing loop, you can wire it like a simple straight track... (that requires an insulated gap). This way your wiring is simplified to :

One rail = one wire... other rail = other wire. 

DCC does not need a continuous loop.  Actually, neither does DC.

sounds like a reversing loop

Pic attached...

Layout picture is attached...  Each color of track is insulated.

Thanks,

Denis

Reversing loop

You can wire a reversing loop with a Double Pole Double Throw switch and manually flip the switch while the train is in the loop, the advantage of the automatic ones is just that automatic.

When you get a picture posted we can give better responses in case you have something more than we are surmising.

Here is the general option of wiring with an autoreverser:

If you want to temporarilyrun trains just replace the auto reverse module with a DPDT toggle switch wired as a reverse switch and manually throw it while the locomotives are in the reverse loop. In the image below, ignore/remove the DPDT in wires from the cab and tread the cab as the wires from the DCC booster.

yes

your red track, which you indicate is isolated, must switch it's polarity automatically to accommodate the polarity of whichever track it is being entered from.  That means it requires an autoreverser.  Please also note that, since that track could easily be entered/exited from more than one point simultaneously, you will have to manage access to this track to prevent autoreverser failures - the track cannot be both polarities at the same time.

Blair

@ Denis..

The red track is a reverse loop only because of the short crossover to the black track in the center.  You will need to double-gap the track a indicated by the green lines and use an auto-reverser or DPDT switch to power that section of track.  It also limits the length of your longest train to one that will fit entirely within that section.  If you have a longer train, move the crossover further to the left.

New Pic

I've added another pic to the first post.  Here is the question/problem, if I have a train entering the red track at point A, I agree the polarity will auto reverse and will match.  But when that same train enters the main (black) track at point B, the polarity does not match and the train comes to a sudden stop.  

Does that make sense?

Thanks for the wisdom...

Denis.

May need more info

Assuming you are not running a train from both the light blue and the black tracks into or out or one in and one out of the red track, i.e. only one train enters/exits from either of those tracks into/out of the red, then treat the red as the reverse loop in the pictures of my previous post.

If you plan to have trains entering/exiting from/to the light blue and black tracks at the same or similar times then you will need additional isolation or maybe you can get away with moving the insulated joint.

Like HVTDave says

Moving the gaps in the straight RED section to the left can accommodate a longer train. BUT there still is the path from the right-hand gaps between RED and BLACK to the gaps in the crossover. If your trains won't fit into that length, consider moving the crossover to the left.

DrJolS

Autoreverser

An autoreverser will flip polarity any time it senses a mismatch in polarity.

As you indicated the different color tracks are insulated from each other, wire the DCC booster to the black track and to the input of an autoreverser (or DPDT toggle), and wire the output of the autoreverser to the red track you should be good.

The only caution is a train has to be is entirely in the red section and you cannot have another coming in or going out of the red section to the blue or black you will be good.

The problem is...

There is no problem entering the loop (red) track, the problem is exiting the loop (red) track.  Might just have to remove the crossover at point B.  I thought it was just an easy way to reverse a train and have it go around the layout in the opposite direction.

Denis.

I'm sorry,

but I don't think you are understanding the function of the autoreverser.  Before we get into a discussion of where to cut gaps, or of train length limitations, you need to understand the following.

Using your original drawing, feed the entire red section with the autoreverser.  Let's presume that, before your train enters "RED", the polarities are correct at left and at right, and mismatched at the crossover.  When your train enters the RED by left or right end, nothing happens.  When the train exits via the left or right, nothing happens.  When your train enters or leaves at the crossover, the autoreverser will reverse the polarity of RED, ensuring that the polarity required for operation is preserved.

At this point, your train is out of the RED area, but the RED section is left reversed, with respect to the rest of the layout.  The next train to enter by left or right turnout will cause another autoreversal.

So what matters is where the autoreversal happens, and it all happens automagically.

But.

Two trains can operate independently into and out of RED as long as you ensure that no one is traversing the crossover.  If a train is to cross the crossover, neither of the other two section boundaries can be traversed, as this would result in conflicting autoreversings happening simultaneously.

Details

- technically, if you run only plastic wheelsets on all cars, and have only head end power, you may consider "train" to be equivalent to "power consist" in the above statement.  Once you incorporate metal wheelsets, or passenger cars with lighting(using metal wheelsets), or put tail end 'helpers' on a train, you need to ensure that the abovementioned restriction is still met - even if it means that your train must be shorter than the distance from the right hand entry to the crossover.

- The track to the left of the crossover is more or less irrelevant, it really needn't be part of the reversing RED section - it adds nothing to the performance of the reversing function, and may as well be wired to the light blue - but it can also remain RED. 

Hope this helps

Blair

@ Denis

In the enlarged drawing below you should be able to see how a loco coming from the left on the black track will cause a short when the wheels hit the red at B.  The left wheel is going from a '-' track to a '+' track.

Eliminating the crossover at B will eliminate the reverse loop.  If you would like to reverse the direction of a train simply double-gap the track at the green lines as shown in my previous post, then power that section with an auto-reverser or thru an inexpensive DPDT switch as Jim B shows in his previous post.

DCC reversing

Oh, I think I get it...

Gonna give a shot next week...

Thanks,

Denis

Works just fine...

Hooked it all up and works as intended!

Thanks guys,

Denis