bajinnova posted:The Lionel RS-1 (RS-I?)
It is RS-"one"; the first Road Switcher (RS). (Their switchers - no short hood - were "S-1" and the like.) In fact, Alco was the first to use "road switcher" as a term, so far as I know. Later came the RS-2 and RS-3 (almost identical visually), and some other RS's, then they quit using the term.