An ex of mine, whom some of you met a while back on the West Yorks challenge was interested in the railway. No where near as much as most of us. She did (does?) have an account on here I think. I didn't know about her interest until we had been dating a while and it sort of grew along side me being more and more open about my interest.
It was good to be able to go on train based days out (Model Rail Scotland, NRM, ELR and do the Scarbourgh Flier etc) but at the same time, it did mean I had less "me time".
My current girlfriend found out about my interest a bit after we started dating, her Dad is a bit of a transport enthusiast, but he prefers trams and busses. She is supportive to an extent, but wouldn't want to be seen stood waiting for a RHTT to pass with me. I don't blame her. The idea of going out on a steam train (eugh, kettles) for a day isn't verbotten.
Basically, don't let one interest of yours define who you are or how you see yourself and present yourself. If another person is worth your attention and time, they will accept your interests, however "odd" they may be. I am not a huge fan of some things that my girlfriend is a fan of but hey, that is life.
Finding girls is hard, just make sure you are in situations you feel comfortable in. I met a couple of my girlfriends in pubs. Don't go into a conversation with a girl with the aim of "I must get her number, I must get a date with her and we must grow old together" just talk to her. As for getting guys, I don't know how or why but they just hit on me. I am not of that persuasion but how are they to know before asking?
I never thought I'd be giving dating advice!