Using SCARM wanted a basic, starting layout, far from finished, that will fit 2 4X8 subfloor boards (12' across top X 8' deep on left) with still a lot to fill in. The roundhouse (9 bay) & turntable is "in the mail". . . am told the RH track is 8"(6"+2"?) the extensive instructions are here. Am still collecting needed track/wire/switches/controls . .