Here's some serious inspiration for fans of narrow-gauge switching layouts. The plan is from a Sanborn insurance map, dated 1915, in Sacramento, CA. The location is just north of Southern Pacific's main yard and shops area, and it is now a big junkyard so any physical evidence is gone, but these plans indicate a large set of narrow-gauge tracks, with switches, serving different parts of the lumberyard. While they might indicate a people-powered cart on tracks, I would suspect that some sort of powered locomotion would be needed in a complex the size of two city blocks. I'd imagine that a steam locomotive would be the most likely choice, although a battery-powered electric locomotive is also a possibility, and maybe more likely due to the fire hazards of a steam locomotive working in a lumberyard! An exact model of this railroad would take around 6x12 feet, but it would be easy enough to compress into a 2x6 or so space, even with a standard-gauge spur in front.