Yes, stable.  Translation: always cool and slightly damp, except by the furnace and/or water heater.

You might want to invest in some DampRid, or something of the sort available at a dollar store or en mass from homedepot.com
Take the lid off the container, set it on the floor out of the way (or between your first and second tiers) and forget about it until it needs to be replaced.

Why did my first readthrough read that as " one of you hoes can measure"?

What's the e for?

N gauge
?
HO narrow 30"

Another option to consider would be a gauntlet track running the length of your single-track section.  A gauntlet track is two tracks on a slightly bigger space than one track.  One set of tracks is offset slightly, maybe 1/8 inch. This would negate the need for a reverse loop as technically, the train is not returning on the same tracks it used to get to there.

I see a naughty sign!

If you raise the third tier enough, you may be able to use N-scale things to 'fool the eye' even more.

As you look at  those track plans, realize that the sectional tracks will not line up right.

By new math, I suppose you mean calculations?  XD

Are you going to add any diagonal bracing for the legs? Or just hope any weight on the tabletop will be light enough not to matter?
(Hint: cross braces are your friends)

Question: How are you going to run a couple DC trains with only 1 pair of outlets? Let alone any scenic lights and overheads.  Use a bunch of power strips?

I think what would've gotten the attention of the train crew was all that wheelslip!

That was genius, it really was.

I hope I'm not up-playing the obvious here, but are you possibly connecting the track and the switches both to the DC side of the controllers?

Quick question Ken.
Who's the woman on the train pilot, reply #10, picture 4?
Just a random train climber?

A lot of times, cheaper places would just paint the entire door, knob and all, to keep replacement cost down slightly.