Tetsuko

If you are a male trainspotter in Japan, you might be refered to as Te'chan.  This is a contraction of Tetsu (iron/metal) used in tetsudo meaing railway, and chan the prefix used for small children.  However being into trains carries little stigma here.  If you are a girl and you're into trains you might be refered to as Testuko.  Ko being a common ending for girls names.

I'm an absolute hoot at dinner parties.