Start of the shelf layout (Model Railroading)

The itch to build an operating HO model train layout got scratched today. Decided upon a thin around the walls layout that allows the guest bedroom to still hold guests. Expected guests are mostly grandchildren, who will think model trains are neat. This is the basement guest room, I have an upstairs guest room for grown up guests.
One wall will have a 2 foot deep shelf for trains, on the other three walls, the layout will be narrower, one foot or a half a foot. I made up some big angle brackets to support the wide two foot side. Gussets are 3/8" plywood. A piece of 1*2 lumber goes on the wall, a piece of 2*3 lumber goes on top. A 3/8" dado in the wall lumber and the top lumber accepts the plywood gusset, and some Titebond II carpenter's glue bonds the gusset firmly into the wood. I made up seven brackets from wood I had kicking around the garage, making the cost of this part of the job zero. I painted each bracket with two coats of left over wall paint, so they match the room's sheet rock nicely.
After an internet recommendation, I bought a Zircon stud finder at WalMart. It's battery powered, $17, and works like a charm. It found every stud, even locates the edges of the stud. The wall brackets went up with 3 inch sheet rock screws, and every screw bit into a stud. Variable speed electric drill sinks the sheetrock screws no sweat. Studs go every 16 inches, making for seven studs from one corner to the other. I put seven brackets on the seven studs and that ought to be plenty strong.