S-Scale is 3/16ths of an inch to a foot or a ratio of 1:64. it fits nicely between 1:87 (HO) and 1:48 (O). S-Scale has always had a small but devoted group of model railroaders and is now enjoying a potentially explosive growth because of the availability of more products than at any time previously.
S-Scale is attractive for many reasons. The size itself is attractive. It is large enough that model detail is easily seen with natural vision. Its dimensions and bulk provide excellent operating characteristics and reliability compared to smaller scales. Even children well under the age of ten can handle S with ease without damaging the details making it fun to play with. S is the only scale that can actually allow someone to participate in scale model railroading and in the hi-rail (toy train) aspects. Many have achieved this mixture on the same track, with one layout and still maintain a true-to prototype appearance.
It is no surprise that even model railroaders who are not active in S-Scale call it "THE IDEAL SIZE". Examine S and you'll see why it is the "S"ensible size.