Just about everything you need to know is posted on the National Association of S Gaugers Site (NASG):
There are photos of past and present locomotives and rolling stock, track, structures, vehicles, and all sorts of tips about modeling in S gauge. There are three basic "camps" in S: 1) American Flyer for those who want to run or collect the style of trains similar to the past; 2) scale for those who want to model as closely to the prototype as possible or "reasonable"; and 3) high-rail, which uses taller track than scale modelers and deeper wheel flanges similar to what the American Flyer locomotives and rolling stock use, but whose modeling can otherwise be as prototypical as scale modelers or somewhat less. The distinction is important because high-rail wheels often do not work on scale track because the flanges hit the ties and because high-rail wheels cannot go through scale switches. On the other hand, scale wheels can work on high-rail track but cannot go through high-rail switches. The NASG site does cover this topic in depth.
