Hadn't heard the story, so I looked it up:Just one Spence, I think the Purdue Lads only painted one.
The Monon Railroad served Indiana, Chicago, and Louisville from it’s founding in 1897 til it’s merger with the L&N in 1971. It’s main shops were located Lafayette Indiana, home to Purdue University. As local legend has it, some aspiring young railfans attending Purdue thought it would make a great practical joke to re-letter a Monon boxcar parked at the local Ralston Purina siding from “Monon” to “Moron” They enlisted the help of students in the art department to create accurate stencils and sneaked down late one Saturday night to accomplish their mission. With the repaint completed, the group waited just outside of town to photograph their handy work as it left town the next day.