I’m in a somewhat similar situation in that I have a rented space where I’m reluctant to build anything too “permanent” and reluctant to anchor too firmly to the walls. I’ve used adjustable saw horses as legs for l-girder frames, and that has worked well for me. They also have the advantage of being movable if I have to access a spot underneath the layout, I simply slide them up or down the layout to do what I need to do. Here are some older photos of when I was just setting this up, you might consider this for legs. I think they run about $30 apiece or thereabouts.
btw, that 10’ long ‘module’ in the first photo is pretty long and heavy, but with a second person to help is easily movable. It has survived three moves already and still operates well.
In my opinion, starting your “dream layout” in a less than ideal environment is not the best path to choose. I’m not suggesting that you abandon the dream, but the further you go with benchwork of any type, the less the chances are that you will ever go back to make the layout room into a pleasant and useful place in which to work.
I’d suggest that you make a couple of sections of open grid (1"x4" or 3/4" plywood cut to similar dimensions, the crossmembers 16"o/c. This will give you some model railroading activity while you accumulate the means to finish the room - studded walls with drywall (insulation if the environment requires it), and proper lighting and electrical services.
I’m not a big fan of L-girder construction, but if you want to avoid legs under the layout, you can then lag-bolt 2"x4"s to the walls, horizontally, at the desired layout height, then use engineered joists to support the aisle-side of the layout. These require support only at their outer ends, regardless of length.
I’m not sure why many people seem to dislike legs under their layouts. My layout is open grid, built in sections, mostly 8’-10’ in length. It’s supported on 2"x4" framing (and some larger lumber, too, all “leftovers” from building my house. These supports are fastened to the studs and the grid sections simply sit atop them, screw-fastened with a few 1"
My previous layout, built in an apartment, is now sitting in pieces in my basement. I built simple box frames, put in a layer of 1/4" plywood, and topped it with 2" extruded foam insulation. Each 8 foot long section had one pair of legs, the other end was supported by the legs of the previous section. The legs attached with bolts, and as I took it down I removed the legs as pairs, folded in the brace that extended parallel with the benchwork, and slid the leg pairs closed on the diagonal braceto make each pair with attached braces into a sompact piece that was easy to move, and then each 8 foot (a few sections were shorter) piece of layout was small enough (and light enough) to be carried out - which was down 2 flights of stairs. Nothing was attached to the walls or floor, so the room was clean once the layout sections were removed. I’ll probably never put it back together, or even use any of the sections as is, but it came down quickly (I was pulling it apart AS the movers took each piece).
Benjamin - About 5 years ago I started my layout in a spare bedroon that is 11-feet by 11-feet. Like you, I built my layout with the intention of getting it out of the room if we moved or I decide to terminate my empire. The finished layout is 8-feet x 8-feet with a donut hole in the middle to access derailed trains, etc. I divided my table into six sections - the largest being 3-feet by 4-feet that are bolted together. These sections are supported by four legs, each with a large plastic wheel made to support a bed frame. The table surface is 40-inches above the floor allowing me ample access to work under it and giving me a bird’s-eye view of the trains. Have fun!
