I've been thrown out of our basement (long story) but have commandeered one of the spare bedrooms now that my eldest has graduated college and has her own place, another is in college and another starts next fall. Just me and my little one who loves trains.
I have room to do an 8' x 10'6" layout. All of my trains are on 8"-12" shelves around the room, so I'm leaning against a rectangular layout that you walk around for fear of bumping the trains and/or shelves. So, I'm leaning toward an around-the-room layout with a step over (or climb under) as shown so my daughter (or guest) and I will operate from inside the layout.
Unfortunately, I don't see how I can get anything more interesting than consecutive loops and an elevated line for my mainlines. Some day I'll get the basement back but until then, I'll have to live with this for the next 10 years.
In addition to the layout pictured/attached, I have built a shelf-layout about 1' below the ceiling, so I'll be able to run 5 trains simultaneously (2 on ceiling, 3 on main). No RR Track plan for ceiling layout, just two loops around the room.
Design considerations: All 3-rail semi/non-scale engines, passenger cars, and rolling stock. Everything I own is rated for 27" or 31" curves. Using O27 tubular track and switches.
Ceiling shelf layout has 42" and 54" curves. Main level layout uses 34" and 42" curves. Just because something CAN run on 27" doesn't mean it should.
I have good number of postwar accessories that I have located in a yard (of sorts).
Would love to hear suggestions for making the mainlines more interesting or make the yard more fun to operate.