Nothing compared to many layouts here but I built an elevated track around the top of my (small, 11' x 11') train room. I wanted it to look good, so of course it took 10x more time and effort than I had intended. I used tube track thinking I'd need to bend and contort to get things to work (plus, most all my locos have magnetraction).
Tonight I loaded it up with ~20 postwar cars and the 'big' dual motor magnetraction locos (GG1, Train Master, F3) pulled 'em just fine. Pictured is a 1950 issue 773 and despite a single motor it pulled 'em fine too (albeit it's geared very very low) though current draw is fairly high (~4+ amps) so probably don't want to do it for too long.
The overhead layout looks very nice. What did you use for the corner shelf portions? You say you used tube track. What diameter curves are in the corners? I ask, because I have one partially built in a room about the same dimensions, but I haven't finished the corners to my satisfaction. Also, I have GarGraves track just laying up there now, not fastened down. I forget what curves I have, I think 054, at least they are fairly broad. I may change and use tubular because I have a magnetraction engine I will want to run there.
Thank you!!