I'm looking to add the S line to my collection... I've already got N, HO and O. Actually, I started out with S (American Flyer Champion steam engine set) as a kid but that set is long gone, almost completely forgotten as to the details. My question regards the motor of the American Flyer S engines... are they of the "pullmotor" variety (brushes and removeable armature) or can (completely enclosed). If both, is there a general rule as to what year they were one and then what year they switched? While I know many have an affection for the pullmotor, I really do like the smoothness and quiet performance of a can. Thanks all!