I am building a “birthday cake” style Christmas layout with 031 curves and 3 levels. I want to put the vertical risers just to the inside of the track on levels 1 and 2 and each risor will be 12". To determine the inside clearance required I made a loop of MTH 031 Realtrax. The 031 curves have a track bed width of 3" so the center of the center rail is at 1.5". I measured the overhang of long passenger cars (from an MTH Amtrack set) and found they overhang 2.25" from the center rail. I also measured the swing on the front of my K-line switcher (also from a late model set) and it was about 2". Therefore I should be able to put the vertical wall at 3" from the center rail (allowing an extra 3/4 inch for an oops buffer). That would put the wall at 1.5" off the inside of the track road bed. This would be equivalent to parrallel tracks on 6" centers so I think I should be fine.
Does my logic sound right to you all?
Jim