Zachary, do you have any doors, closets, or other nonmoveable obstructions to affect your 8 x 12 space? If you have the full 8 x 12 to work in, the layout plan that Fred linked to could easily be expanded from 8 x 9 to 8 x 12 by adding a 3 foot section on each 9 foot side. If you would rather not duck under to get to the opreating pit, a simple draw bridge or swing bridge could be easily adapted to the design. I think that layout's bench work is only about 12 inches wide. You could add more industries or scenery to it by widening it to 24 inches in some places and still reach across. The web site reccommends 4 axle diesels and 50 foot maximum car length because of 24 inch radius curves. By widening the corners to allow 30 inch radius, and using #6 switches instead of #4s you could run modern long equipment. All in all I think that is just about the perfect design for your space.
