I'm in the process of building an HO layout, which has a lower level staging area. The incline to that area is 2%, and at some point will "disappear into the ground" of the main level. Sooo, I need to determine the acceptable minimum vertical clearance where I can put the main level plywood over the inclined track - and of course not have clearance problems.
Yes, I have NMRA gauge(s), that indicate (if I read it correctly) a minimum clearance of 3 inches from the top of the railhead to the "ceiling". This seems a bit low to me, but I'm not disputing it. I'm thinking 3 1/2 inches might be "better", but I would like your thoughts on the subject.
By the way, I model the ATSF / IC in the '40s/'50s, and have some large BLI locos, and some dome passenger cars, and other bigger than usual cars.
Thanks, your views are always appreciated!