I started out my layout with some vague ideas. I wanted a hi-rail thing but with Lionel tubular track. I only had space for a 16x17 foot platform. Around the walls wasn't practical because of my "old house" basement. So I bought Lionel tubular. Then I discovered that the geometry of tubular track and turnouts is such that I could get 3/4ths more layout in the same space by switching to Gargraves. This I did...and slowly sold off all the Lionel tubular I had bought.
Then I tried to design the layout on RR Track software. I got really frustrated. I wanted to run trains--not sit in front of a PC screen for endless hours. I gave up on RR track (no reflection on the software. It's just my impatience). Instead, I canvased every book and magazine with track plans that I could lay my hands on. While I did this, I built the benchwork using a metal frame that I had in the garage (it was originally a rack for VHS tapes in a Blockbuster store! I bought it at their going-out-of-business sale). Then I made the platform out of 2 inch styrofoam and 3/8 inch plywood--making a THICK sandwich. I wanted to deaden noise with my sandwich.
Also during my research phase, I bought mostly used Gargraves track and turnouts. Little did I realize that my purchases would have been good for a layout TWICE the size of the one I had space for. But my research paid off and I found an old Armstrong plan for the Milwaukee road and Avery yard that fit my general ideas. I extracted the yard design, which is on a curve, and laid the yard on my platform. This and the engine terminal are just about the only flat portions of the layout. The rest is all grades, bridges and tunnels. Of course, at the time, I knew none of this--there was no plan. I just wanted grades, bridges and tunnels.
In fact...everything was done to excess. It is my first (and last!) layout. I had no idea what I needed. So i bought built structures and kits enough for at least double the layout I space I had available--yeesh. And in the middle of my buying orgy, I found a guy who had dismantled a layout and had the Ross switches from it for sale--mostly used, but some new, mostly with 2500 switch machines but some DZ-1000 with 1008 relays. The price was too good to pass up and I am thinking these could improve my layout reliability 100%. It was a package deal for 50 switches, all in original boxes. Many curved switches included (I didn't realize how much curved turnouts can improve a layout design until I started applying these). The upshot is that now I have 50 or so Gargraves switches I have to sell--ugh.
So here it stands--unorthodox benchwork supporting a platform sandwich, on the occasion of the end of track-laying. The track is done. The engine terminal track and tentative structure arrangement (very important to me) took months. I have a couple things to fix (MORE mistakes!). Pix of the metal frame benchwork, the platform sandwich, my 3-bridges-over-the-river-cry and the almost-trackworked-but-far-from-done 
engine terminal are below. Lots of mistakes, but a good milestone.
Don Merz
