RUGSY3,
Copied from a post several years ago: "Prior to 1920, all of what were called the "Pennsylvania Lines West of Pittsburgh and Erie" were operated by a separate organization, that was actually an amalgam of the Pennsylvania Company, a holding company for the lines between Pittsburgh, Erie, Cleveland, Ashtabula and Chicago, and the PCC&St. Louis, which controlled the lines to Cincinnati, Indianapolis and the Bradford-Chicago line. These companies were managed by a separate "Lines West" organization, which only had the president in common with Lines East. This organization used the service mark or trade name, "Pennsylvania Lines" as a contraction of "Pennsylvania Lines West of Pittsburgh and Erie." It owned its own equipment, which was so marked, as opposed to Lines East, which was marked "Pennsylvania Railroad" or "PRR." Got that
Anyway after 1920 "Pennsylvania Lines" went away and all PRR equipment received "Pennsylvania".