Design decisions

Design decisions so far (also see schematic above):

1. Peco Code 55 N scale track, with electrofrogs: reported to operate well (electrofrogs are good for short wheelbase engines), look fairly good, but still be able to run deep flange cars like Microtrains' releases. No minimum turnout size specified yet.
2. 11" minimum radius: allows turnback on the shelf but can run the trains I want (i.e., Kato's N scale RDC is supposed to operate on curves as tight as 9 3/4"). Won't look great, but the only tight curves will be in staging. The visible layout will just have very broad curves (though need to think about curves through turnouts).
3. Train length: maximum train length is set at 37", which is sufficient for a train of ~10 freight cars. Visual tests suggest this looks like a moderate-length train, at least to me. Passenger trains should look much shorter than freight trains, so this means my passenger trains will probably only be two, maybe three, coaches long. It'd be great to run freight trains of 30 cars, but I don't want to devote that much space to staging (storing a train of that length at each end means about 14' of the 19' length would be used for staging, though of course you could stage in other ways) and I want to have trains short enough that they visually go from one "place" on the layout to another "place".
4. Shelf design: metal brackets on tracks mounted to studs supporting a 1x2 frame (with 2x2 pieces running the length of the layout) covered with a layer of 1/4" ply. I will be putting 2" foam on top of this.
5. At each end, an automated sector plate with a turnback curve and storage for three or more trains. One prototype built, still tweaking it.
6. B&M main line going from one end of the layout to the other (basically on diagonal across the 19' x 2' layout footprint). This line has most of the focus and development (yard, industries). The intersecting railroad will run on the opposite diagonal and may be hidden or at least obscured over some of its length. There will be a crossing and interchange track where the lines intersect. These lines will connect to the sector plates at each end.
7. A sneakback track at the back of the modeled layout (hidden with a low hill or other scenery, but accessible). This allows trains to run from one sector plate to the other. For instance, an RDC could run from left to right across the visible layout, enter the turnback loop on the sector plate, run on the sneakback track to the other turnback loop, and repeat the trip. This allows things like a commuter rush in one direction to be modeled with one set of equipment.