Tom, if you look at the 2nd photo in my post on 8-14, you’ll see there’s another crossover just past the bridge. The yellow and blue are dual mains and the yellow is not intended to be an assembly/storage track, though it can be used as such when desired. The crossover spacing is so there is a runaround for when Bob wants to run clockwise. The only way to run clockwise is to pull cars out of the yard, place them on the yellow track between the turnouts, then runaround to pick them up from the front. Then the process will have to be reversed to push them back into the yard.
When it comes to spacing between levels, TrainRoomGary has found 18” to be optimal on his triple deck layout and that’s what I’ve suggested to others. I only placed it at 12” as a minimum here to point out to Bob that 6”-7” won’t work as originally drawn. 15” might be a good compromise though, it’s all up to Bob.
