You could remove the sentence I quoted, keep the thing from the conductor about bison, and it wouldn't make a difference to the story [1]. It's a "lead in" only in the extremely literal sense that the one sentence comes before the other one.
[1] It might even work better, since it lets you draw your own conclusions about the anecdote. Not everything needs to be a lesson.
[1] It might even work better, since it lets you draw your own conclusions about the anecdote. Not everything needs to be a lesson.