I too on a quick look suspect you have built in at least one reversing loop. What I would suggest is to use an accurate track layout diagram showing both rails and all switches (track planning software is a great help with this.) Start at a convenient place and with two different color highlighters continuously trace each rail through the entire layout including all switch branches, one rail in each color without stopping. If you suddenly run the one color into the other color, you have found your short!

It's hard to suggest a fix without a track diagram/wiring diagram but one thing springs to mind. Are your bus-wires open-ended? They shouldn't form "loops", even if the track does. Someone else will probably know more, and explain it better but, I think, you'll need a break in any loop on the track too, a couple of insulated fishplates should do the job. Something I would maybe try, before making any changes: try powering each side (inner + outer) with a simple *DC* controller. That would maybe identify any simple problem and, if it works fine on DC, it must be a DCC-related gremlin. Hope that helps.😁 Cheers for now, Dougie.

Layout looks great 👍🏼 do you have any areas that act as a reverse loop? If so that would cause a dead short

Check your turnouts. I made the mistake of buying insulated non insulated turnouts the non insulated needed to be insulated from the main track. Just a thought. Good luck

Great video this is stuped but do you have any thing laying on the track to short it out ?