Recently I found a web page of track plans fit for both N and HO-scale table top pikes chock full of fun options to play the 3-D game of model railroad operations on called “The Mad Trackplanners Page.” *
As you can see, these plans boldly squeeze in not only industries, but tiny railroad yards as well! One even has a whole bunch of industries to switch connected with a complex web of track.
My favorite has got to be the track plan that has a two-stall engine house, four-track yard, four industries served by three spurs, and an “interchange” track; talk about a lot of operational fun in a small space! Just mind the equipment size, folks: small steam engines or four-axle diesels only, and no mondo freight cars like auto racks!
As far as bigger train layouts go (especially club ones), the sky is pretty much the limit operations-wise depending on how big it will be and what you are modeling. It’s as simple as that. Ditto the modular pikes out there like the HO and N scale ones built and operated by the Minnesota Free-mo Modelers.**
And speaking of modular railroad clubs, long ago there at least used to be an HO-scale Minnesota-based one called the New Brighton connection. The core of their modules was a double track main line for show purposes and a separate track with on-line industries for switching.
And there you go: more notes on model railroad operations, one of the most fun aspects of the hobby.