While beginners often use these terms interchangeably, American model railroaders usually refer to the “scale” they work in, while UK railway modelers will talk about their “gauge.” Ironically, the usages of the terms “gauge” and “scale” have become culturally reversed. The National Association of S Gaugers, Inc. (NASG) is an American institution, while the S Scale Model Railway Society is based in the UK. This may be because early 3/16th scale models shared 1.25" gauge three-rail track with 1:48 O scale trains. During the mid-1930s Cleveland Models introduced 1:64 scale model railroad trains in the United States. For a time, the 3/16th scale was referred to as the “CD” scale for “Cleveland Designed.” CM produced static display models, but powered chassis kits for them soon followed. The best known CM locomotives were a PRR 0-6-0 switcher and a Chicago Great Western 4-6-0 Ten Wheel. Today one running CM locomotive is still purported to exist.