Bob, I don't believe you did, but I may have missed it. Either way, that suggests the upper level will be on a separate deck that will cover parts of the main level. Right now it's only elevated 6" and that's not going to be enough to reach under to deal with problems. Even with a higher elevation, you'll likely need some removable hatches in the reversing loops. Here's a version with the deck and tracks elevated 12".
