I am Not a teen, an old man of 30 years!. Anyway, I have a My Space page and I have found more young rail-fans on there, the biggest surprise is I have found several young female rail-fans even, that was a shock[NO OFFENSE EVER MEANT], just going by what I have encountered in my personal in "the field" experiences.
I think that one problem that I know I encountered when I was just getting "into" it in about 1990 was that every "regular age" rail-fan I met sort of couldn't stand my enthusiasm for the railroading of today. They would sort of give Me a funny look when I would excitedly talk about going out and rail-fanning the CSX and that CSX was the coolest railroad around, one thing they didn't like is that I actually called it the "CSX" not the "L&N" "B&O" "Monon" or some old company name of a road that I never saw in person, that still pisses Me off to today how rail-fans refer to today's Class 1 super railroads by their pre-merger predecssor names, especially those[this is Me] that refer to the part of the BNSF Railway[my favorite now] as the "Santa Fe", I could not stand that railroad because they thought they were "God's Railroad", at least that's the impression I got. The red & silver "Warbonnet" is ugly as hell!!!
Other issues are that some fans I still meet can't grasp onto that us Younger rail-fans don't shoot slides, even if they cost $7.99 a box!, all these negative attitudes caused Me and probably others to consider not following the rail-fan "hobby".
Don't detach yourself from older rail-fans, they can teach You lot, especially about old lines that are now abandoned if your interested, etc. But the best thing is if You can find a group of younger people in your area or region and try to start a group that gets together to go out shooting once a month. just my Idea.