Most were red, so they could be easily seen, I'm sure the first ones were the cheapest available color painted iron oxide wood design.
Since there were at one time 2-3 personnel in a caboose, and another 2-3 in each loco cab, redundant job titles got abolished. And the cost of maintenance on caboose's, and storage problems, not to mention that modern technology and computer waybills, made crew members that rode along inside a "Crummy", "Hack", "Bobber" on the tail end of a train, were now obsolete un-needed job titles, and were abolished.
I remember as a kid I walked up to a caboose with a train sitting at a signal, on the Nittany & Bald Eagle line in Milesburg PA, and chatted with the old fat caboose crew, who told me to: "Stand Back, brakes are releasing, we're on the move, we'll probably tie up in the Williamsport yard, and that will be the days work". I don't even think RR crews had 2 way radio's way back then, and hand crank trackside phones were used for communication to the dispatcher.
Most caboose's had an 11" poured concrete floor, to add weight, so they wouldn't get whipped off the track on high speed curves. I'm sure the many rear end collision fatalities of caboose crew members, also led to their abolishment, deadlining, and scrapping
A colored flag, a flashing amber Star Marker, or a flashing red EOT FRED soon replaced the cabeese
Trains are not cute, charming, pretty, nor sexy (unless one is sexually titillated by the sight of choo choo's) ... They are but a lowly means of transportation device ... I was told: "It's just a job, you're not supposed to actually like the job, as a hobby" !