Getting all the trains out and inventorying them to see what you want to pass on to others is a good idea, Peter! The walls look very impressive now.
Richie does have a point about sawdust, etc. I kept my few trains in another while doing the heavy construction, but in an 11x11 room I couldn't do it any other way. If I recall correctly, you have a good bit of room to maneuver between your shelves and planned layout. Dust would still filter over, unless you had someone using a shop-vac to pick up everything as it is being cut. Or....do you have a special sawing room, that will be sealed off from the layout room? I know you thought of everything!!! 
