Interesting idea.
I'd say you definitely need more then a circle of track around someone's backyard (not that it wouldn't be nice if it was your back yard).
I plan on having it be a 'club layout', not in someone's backyard. I'm going to have it use similar topography as Train Mountain, the largest live steamers railroad in the world, but it would not be as long, around five miles instead of 25. I must note that I'm using the content currently available to create the variety of rolling stock you see at a live steamers railway.
From the videos I've see multiple routes, at least one tunnel and one bridge, facilities to add water (like 12 inch to the foot steamers these use more water per mile then fuel).
I am going to put in a few bridges, but I'm not certain about the tunnels. I will include places for water.
One unique facility would be where owners load and unload locos from the back of cars, pickups, trailers, etc.. From photos I've seen these allow the transporting vehicle to go down a ramp so the track on the vehicle is the same height as the track on the ground. Easy to load and unload (though I don't know if this is done before or after stoking up the loco). My guess would be before so as not to tie up the load/offload ramp any longer then necessary.
Given that I'm using full-scale rolling stock instead of 1/8th scale rolling stock, I don't know how that would work out.
I've also seen a photo or two of a turntable but not an associated roundhouse. Possibly used for storing locos while they wait their turn on the main line.
That I'm planning on doing.
Storage tracks for whole trains and some passing tracks as there is no reason trains can't go both ways.
I plan having the mainline double-tracked and single-directional. But I am planning on having two reverse loops so that trains can turn around.
Center to center track spacing is much wider then normal from what I've seen.
I'm uncertain how to do that in the yards, but I can do that on the mainline.
Finally - a lot of these either have separate routes for different scales (usually 1/8 scale and 1/12 scale) and some even have dual gauge track.
I was just thinking about just doing two routes using the track plan, but one is narrow gauge and the other is standard gauge. I'll look into dual gauge so that 3-foot and standard gauge trains can run on the same track.
Should be a fun project - good luck.
Thanks, I'm going to need it.
. . . not that it wouldn't be nice if it was your back yard.
Well this guy's backyard railroad, which has been around for over thirty years, makes his electric bill go thru the roof when he uses it:
Short ride on the railroad: