I always appreciate the information shared on this and other OGR forums. I learn a great deal. In this case, thanks to the post and photos by Wood, I might construct 1 or 2 shelves on the edge of the layout to hold the few items of rolling stock that alternate on the layout. As noted in my previous post, these items are kept in 2 shallow plastic storage bins under the layout, but inevitably, they are always under some other storage bin, or are otherwise awkward to access 
. I still need access to the space under the layout, so anything I construct must allow that.
Thanks,
Michael
