If I'm thinking about the right tale/joke/line, it was one I used to set up any of a number of train/cow songs then on my song list.

It was about a train that went so slow that they took the cowcatcher off the engine and re-mounted it on the caboose to keep the animals from boarding the train and trampling people.

It was the Amtrack line---here in the USA---which never ran on time in those days. A hobo I knew lay down on the track to commit suicide----and starved to death !

Art Thieme