I'm mostly a lurker, but I'll pipe up since asked. As a kid in Los Angeles  I would occasionally see engines in normal (yellow/grey or scarlet/grey) with strange lettering like MISSOURI PACIFIC or COTTON BELT.  Clued me into this being a big country with many names.  I grew up, moved to Colorado, and started modeling the Grande in the 1950's and the Mopac is an important partner in traffic and reefer supply