In my canon I see C.B more as an entity rather than a real piece of rolling stock, My canon as him being sorta as a cryptid or anomaly is to try to make the song make more sense with some of the lyrics. (this is my canon of c.b): The caboose anomaly, better known with his nickname C.B. or sometimes referred to as the devils caboose, given by railroad workers, is a red caboose that appears randomly in train yards whenever he wants to cause chaos, he is hooked to the rear of trains whenever there is no other caboose around, He has no identification number or any road name, he is just a stock standard caboose, which makes it harder when railroad workers try to explain him away after he wrecks a locomotive, He does have the power to cause train crashes, which leaves crews confused on how a perfectly non faulty locomotive could lose its brakes, even after said locomotives were just tested or repaired earlier, and has gotten both crew and locomotives injured, dead, or scrapped, he has the ability to shape shift into international cabooses or break vans, causing more trouble in other countries, while America has the End of Train Devices and no longer needs cabooses, He sometimes can be seen alone in yards as freight trains go by, crews are unsure, but they swear they hear a cackling laughter coming from him at night, looking for his next victims. The insane and non insane faces is to keep true to his introductory part in freight, then him comforting Diana in there's me, and then revealing to greaseball and Electra that his is secretly a murderer that causes train crashes.
(missed chance to crossover him with bruno the caboose ;-;) Me Domix Karin Andrew lloyd webber