Ok, lets see how much we can argue about the upper level return loop. 
I believe the whole return loop + staging tracks will be inside the reversing section.
The double gaps need to be far enough away from the curved turnout (that introduces the need for a reversing section) such that the PSX-AR controller has enough time to throw the turnout to match the correct direction when a train is exiting the return loop towards the turnout.
Simple, right?
FF, if the concern that you are expressing were in fact to occur, the short would happen a lot sooner than when a train moving from right to left on the bottom track in the lower diagram passes the crossover and meets my proposed reversing section. In other words, as the train leaves the upper track in the lower diagram (that is moving from left to right off the diagram, somewhere beyond that, the train would encounter a black rail meeting a red rail and a red rail meeting a black rail. Think about that scenario.
Yes, correct, it is a reverse loop in the classic sense.
Rich
I agree Rich. As soon as you switch the wires on the lower track the short will occur, has nothing to do with the train. Red meets black= problem. nowhere near your proposed reversing section. As I said, lets see what works for Onewolf42.
But only inside the isolated reversing section and the A-R will correct that very, very momentary short.
What do you know Rich, we agree on the upper reversing section
How will changing polarity inside a reversing section to the left of the crossover correct a mismatch when the upper track meets the lower track, as wired in your lower diagram, somewhere to the right of the crossover?
We are going in circles, lets see what works for 42.
Yep, we agree to disagree.
Actually Casey_Dowling had it right, right from get-go. Just move the right most gaps farther to the right to gain length.
Kicking a dead horse, are we? 
No one said that Casey was wrong.
But, as I said, why mess with the crossover, just gap to the left of it.
As Onewolf showed in his initial drawings, both tracks, above and below the crossover are wired the same way, so there is no possibility of an uncorrected short.
Given the diagram you show , if you follow the lower track B around the loop., you end up on track R. It was my contention that the upper rack has B on the outside and R on the inside so removing the crossover would make it a normal loop, B on the outside and R on the inside. I don’t see anything in the original diagram showing anything different
OK, I see why you are confused. That segment of track that I showed with the vertical red line drawn through it is from the original diagram that Onewolf posted. What you are missing is that the loop on the left side (which does not appear in Onewolf’s diagram) would actually be Red on the top rail as it loops around to the top. That is because that upper track in the diagram with the Red rail on top comes out of the loop on the bottom such that the Red rail which was on top is now on the bottom of that lower track.
Therein lies the problem - on the lower left where Red meets Black and Black meets Red. A point of opposite polarity, causing a short.
How to resolve it? Create a reversing section.
Where? On the bottom track from the lower left to the bottom track, say, right where that red vertical line crosses the lower track, that is, just before the crossover.
That reversing section will always change polarity to accommodate a train entering or exiting the reversing section from any direction because the auto-reverser controlling the reversing section will sense a short due to mismatched polarities and correct the polarities inside the reversing section.
Rich
We agree the red on the top becomes around the loop and is the red on the bottom. Same rail same polarity. Thus when the crossover is installed the red on the bottom is connected to the B rail on the top and the B rail on the bottom is connected to the red rail on top, thus the need to gap the crossover. His layout appears to be a loop to loop with the same rail having the same polarity throughout the layout.
Forget about the crossover. The proposed solution takes the crossover out of play.
Go back and look at Onewolf’s original diagrams where both “mainline” tracks are red over black.
That is what creates the short and, thus, the need for a reversing section.
Keeping the crossover out of the equation, so to speak, simplifies the solution.
Rich
Where are you getting the op’s diagram showing red over black on both mainline tracks, top and bottom. I see nothing of the kind? As you said red all the way around, red on top of the upper track and red on the bottom of the lower track. no crossover, trains run with no problem. Same rail same polarity throughout the layout. No reversing sections anywhere. Which is what I believe 42 has now.
Where are you getting the op’s diagram showing red over black on both mainline tracks, top and bottom. I see nothing of the kind? As you said red all the way around, red on top of the upper track and red on the bottom of the lower track. no crossover, trains run with no problem. Same rail same polarity throughout the layout. No reversing sections anywhere. Which is what I believe 42 has now.
Sorry, but I don’t think you have a clue what’s going on. There’s a reversing section between the lower return loop turnout ladder which ends before the crossover. No need to double gap in the middle of the crossover. The entire rest of the lower level has the same polarity other than the reversing section.
@floridaflyer1 it appears you’re envisioning this wired like a “dog bone” layout with the sides of the bone brought together to form a double track mainline. That is certainly a legitimate way to wire many layouts, in fact, my current layout is temporarily wired that way, but it often does not make sense. One of the driving factors is the number of crossovers between the mainlines. With an outside/inside wiring scheme, every crossover requires a reversing section, but the end loop(s) do not. With a top/bottom wiring scheme, the crossovers do not require a reversing section, but the end loop(s) do. If you look at his other posts, you’ll see that there is at least one more crossover in addition to the one at question, and I suspect there are more. There is also only one end loop on the “dog bone” (@Onewolf42 it is always best to post the entire layout or as much as possible when asking about wiring). In this situation, top/bottom wiring leads to one reversing section while outside/inside leads to at least two, maybe more.
