It also depends on how busy the line is: sometimes a passing siding is no longer needed as such, or the pace of things is such that there's time to wait while a car is loaded or unloaded.
I just grab one of Ian Wilson's books about CNR branchlines in southern and central Ontario. If you're not familiar with these books, the photos and writing follow a train (actually a composite of many trains, as the photos are from a wide variety of photographers, and most were taken at different times) along each line, and there's usually a trackplan for each small town. Flipping open Steam Over Palmerston, on page 43 there's a trackplan for Wingham, circa 1955. In addition to the mainline, there are 4 separate sidings (single-ended): two of them serve a foundry, one is for some coal bins, and the fourth is elevated for loading grain into trucks. . Situated on the mainline is the passenger station and a water spout. There is a passing siding running alongside of the main, opposite the station and water spout, and located there, from west to east, are an oil dealer, sheds of some unspecified type, a grist mill, more sheds, and a coal bin. Another track, also double-ended and a bit longer than the passing siding, runs behind the station, and located along it are: a lumber yard, a freight house, coal shed, teamtrack loading ramp, stockpens, and another two oil dealers.
Obviously, the possibilities are almost endless.:thumb:
Wayne