The classic sytle Caboose had a cupola on top so the crew could inspect the train from the perch. I was told by a gracious volunteer at IRM that as train cars got taller the cupola was no longer useful for the Train Crew to do their job, which was partly to monitor for smoke coming from the wheels that signaled an over heating condition. Prior to air brakes, the brakeman would also ride the caboose and from front to rear would go from car to card to apply the brakes. This ensured the couplings between the cars would remain taunt.
