What I realy need is a 30 second (or shorter) explanation of my railway interests before the listener switches off or comes back with a predictable joke.
"I am interested in trains" is answered with "So you're a trainspotter then" or "Where's your anorak?"
"I am intertested in Heritage Engineering" stops the jibes, but sounds rather pretentious.
"I love the smell of steam and hot oil in the morning" gets them backing towards the door !
and is a rotten chat up line as well.