My layout is quite small for O Gauge (17x18). I started wth a general track plan that was originally published in John Armstrong's Creative Model Railroading book. The layout featured the Milwaukee Road and Avery yard and lots of catenary. I had no interest in any of that, but the yard design gave me a good starting point, size-wise, because I realized it would fit into one corner of the layout rather nicely.
I did the benchwork for an island-type layout and laid my version of Avery yard directly on some 2 inch foam sheet backed by 3/8 inch plywood. I used a technique for screwing down the track I found in a magazine where you Gorilla-glue screw plugs into the foam and then screw into the plugs once the glue dries. This works perfectly and I have since laid a couple hundred feet of track this way--directly onto sheet foam.
The far end of the yard would exit into a helix going up and also into a big diesel/steam engine servicing terminal. What to do with the near end and how to connect with the engine terminal and helix is where I got hung up. At this point, I had exhausted all my ideas stolen from John Armstrong. Now I was on my own.
It was only last week that my brain cramp came loose and I figured out how to swing the yard exit tracks up and double back across a **** Gate bridge and then S-curve into the top of the helix. And that is where I am. I just pulled some plywood out of the garage that will be cut into helix semi-circles. The helix will be supported by threaded rods. The lowest loop of the Helix has 3 exits: 1) back into the yard from the far end, 2) back toward an open area in between the yard and HG Bridge, and 3) out the other end toward the engine terminal.
It's all in my head, nothing on paper. Cut-n-try with Gargraves and Ross. But the Helix is Ross 054 sections because I hate bending Gargraves track into 054 and tighter--I always mess it up. I am taking every short cut in the book and "rules?? What rules?" But I did keep grades under 4%. Everything else is fair game.
All the best!
Don Merz
