Wish we knew who made those decisions and why, Jim.
In a nutshell, the first three RS2's were delivered by Alco in early 1947 in a black-and-yellow scheme with the steam-era red-and-white "lozenge" herald on the cab side and large white script "The Hoosier Line" on the carbody sides. Later in that same year, the rest (6) were delivered in black-and-gold with the white MONON's on their carbody sides with smaller "The Hoosier Line"'s below them and round red-on-white "ball-M" heralds on the cab sides. Then through the 50's and into the 60's, the lettering schemes were gradually simplified as the locomotives were shopped, first by dropping "The Hoosier Line"'s, then the heralds, and eventually on some units substituting gold or black lettering for the white so that just prior to their 1964 rebuilding, no two RS2's seemed to have exactly the same scheme.
