Train Nonce
Someone who is completely obsessed with trains to the point that the person acts sexually towards trains and describes them/talks about them in a sexual and obsessive tone and/or refers to them with sexual nature.
Me: What you been up to, Alex?
Alex: Been takin' a look look at some reet sexy trains ;)
Me: You fucking Train Nonce
Alex: Been takin' a look look at some reet sexy trains ;)
Me: You fucking Train Nonce