[Doug]

I have the following set up on my layout.

This is a classic dog-bone layout:

With DCC, when you cross the tracks in the center section, without proper protection a short will occur:

To remedy the situation, you add a couple of reversing units to either end:

This allows you to keep all the DCC "polarity" the same in the center of the layout. This is where the stations and most of the activity occurs. It will help with wiring and reduce the chance of shorts.

 

[Doug]

Perhaps, but my layout has all the stations and yards in the middle section. I can have a couple of trains running on the dog-bone mainline whilst I pass the time shunting in one of the yards. The extra reversing unit takes out any chance of a problem. All the track in the green section below has the same polarity: Red at the front, Black to the back.