"rail way girl" joke

A railway inspector and his friend in a bar chating...
Friend: Why have you got that big smile on your face.
Railway inspector: I just had the best sex of my life!
Friend: with who?
Railway inspector: With this girl I found on the railway tracks.
Friend: Oh yeah! What did she look like?
Railway inspector: She had the most amazing body!
Friend: Oh yeah! But what did she look like?
Railway inspector: She had the most amazing legs!
Friend: But what did she look like?
Railway inspector: She had perfect breasts!
Friend: Yeah but what did she look like!
Railway inspector: Don't know never found the head.