Oh and as for trains, You'd best decide if you're going to go with one locomotive or two.
With two, you can do a short-haul 0-3-0 tank engine without tender (a la Thomas) and a longer express/freight model, perhaps on a 2-4-0, 1-4-0, or 1-4-1 design, with a tender (there are larger, but then half your table length would be loco!).
If you're just doing one, a compromise is something like a medium-haul 1-3-0 or 1-3-1 setup, either with a longer built-in coal bin (tank-engine style again, just a bit elongated) or the sort with a half-length tender.
If you're baffled as to what I'm referring to with those numbers by the way, that's the nomenclature for locomotive wheel configuration, with left to right reading front to back of one side. So a "2-3-1" would indicate an engine with two small wheels forward of the driving wheels, three large drive wheels, and one small wheel under the cab.