It just occurred to me, I have no idea whether S scale is three-rail AC like the O scale it was intended to compete with, or if it is two-rail DC. Anyone happen to know off-hand?
Some of the American Flyer equipment was 2 rail AC but the scale equipment sold by American Models and SHS Helper Service are 2 rail DC. With that being said, both of them sell AF compatible AC engines with electric e units to reverse direction. Also the AF compatible equipment has larger flanges on the wheels and AF style couplers. For the scale equipment, Kadee couplers are available. Greg Elems
