Avoid the kitchen
Thanks to you both. I am researching and hope to come to a design decision. I had been thinking of a shelf and am glad you commented on visibility, I was wondering about that myself. The closer to the ceiling and smaller the room, the angle of view could be such that if you were seated, you wouldn't even see the train from some angles! I wanted 2 parallel tracks, but thought I might not be able to see the inside train at all from some angles.
My first idea was wood suspended by metal rods, but that now seems too much trouble. I will probably use a ledger board and brackets. The shelf will be about a foot from the ceiling and run in a large oval running through openings between my kitchen and the formal living room. The kitchen has a breakfast nook with a bay window, so that will be the focal point. But as it runs through the dividing wall with a large opening to the living room, there is nice seating there too and it is where we put the christmas tree every year.
FlightRisk;
Unless you want to change your screen name from FlightRisk to FireRisk, I suggest you do not run your railroad through the kitchen. Poking holes through the kitchen walls, up near the ceiling, creates a perfect path for a kitchen fire to spread very quickly to the other rooms of your house. The kitchen is where most house fires start. The wood, or plexiglass shelf will burn, and the plexiglass will also generate large quantities of very toxic fumes! I don't know what "ledger board is, but I'm guessing it's some form of cardboard, which also burns, and lights off at a lower temperature too. Your local fire codes may well forbid poking holes through kitchen walls. Christmas trees are another common "point of origin' for house fires. Having holes high in the walls means a tree of fire could spread through the house equally rapidly. I strongly recommend keeping your railroad out of the kitchen, and setting up the christmas tree away across the living room from the railroad. I also suggest you check your wall-piercing plan with the real experts, your local fire department. They can advise you on any fire hazards involved. Please be safe, not homeless, or dead.
Even if, (as we all hope), you never have a fire, the normal kitchen cooking grease, and dust will rise up and get on your track. This will quickly be spread along the rails until your train won't run, because it can't get power from the rails. That will mean getting up there, and cleaning the track, which will get very old, very fast. I don't know your age, but the older you get the less fun climbing up on something to clean the track will become. I do assume you are a bachelor, since you speak freely about cutting holes through the walls. As a long-married man, I know that wives tend to frown severely on such behavior!
Have safe fun;
Traction Fan:smilie_daumenpos: