One Train Hears Another

Why makes this Joke funny?

The joke "How does a train hear another train coming? With its engineers." plays on a pun, which is a form of wordplay that exploits multiple meanings of a term, or of similar-sounding words, for an intended humorous or rhetorical effect.

Here, the pun is on the word "engineERS." In the context of a train, an "engineer" is a person who operates the engine. But the joke plays with the word "ear" within "engineers," making it sound like a body part used to hear, even though trains, of course, do not have ears and cannot hear.

Puns often derive their humor from using a word in a context where it has a different meaning, creating a surprise or unexpected interpretation for the listener. This joke is funny to some people because it creates an unexpected and absurd mental image of a train using its engineers to hear another train coming.