>>55588Space should never be an issue when it comes to model railroading. Micro layouts, pizza layouts, etc. take up very little space.
http://www.carendt.com/Inglenook Sidings are part model railroad and part board game, setting out and picking up cars.
http://www.wymann.info/ShuntingPuzzles/sw-inglenook.htmlExpense is only an issue if you buy brand new stuff, there's plenty of decent running older engines and even some brand new things people sell low for various reasons. Track is very cheap and, again, can be purchased used.
Structures/buildings can be free too, cardstock and veneer plywood can be had for free. Rolling stock, all you really need is screws, trucks and couplers, everything else can be made of cheap balsawood or basswood and bits of brass or styrene.
As always buyer beware with the used stuff, train shows are the best way to find good deals.