I've been missing...

[otiscnj]

I'd push the layout out to your 40" circle, then give yourself a little bit wider open area in the middle. The wider you make the middle, within reason, the more user friendly it will be. You might also be able to double deck this design by running a nolix around the walls to a second level...that could double your modeling area.

 

[Janry]

With that amount of space I would be seriously considering N scale.

My biggest concerns with N scale isn't so much with the locomotive and rolling stock size or the soldering anymore. I'm more concerned with the N scale scenery, structures and figures size. Also, less selection in N scale than HO scale.

You might also be able to double deck this design by running a nolix around the walls to a second level...that could double your modeling area.

I am fascinated with helixes and nolixes. I hadn't really wanted to bring this up at this time but might as well now. That doorway (no actual door) to the basement area is 5' wide and just inside the basement to the right is a 5' x 15' area I plan to expand to as I near completion of the garage area. I would use about a foot of that doorway and build a railway from the garage to the basement and I've thought it would be fun to build a nolix around a mountain in the basement area, then re-enter the garage area on a new level. My only concern is the best way to build the elevated area in the garage space. I'm thinking of building a vertical framework at the edges of the proposed first layout with joists attached that are near the garage ceiling, then suspend a platform from those joists with steel rods.