Another factor that would help is remembering and reminding other members that disparaging comments about "today's kids" and making them feel like they are not welcome is NOT a good recruitment tool.
When I started working at Portola, I was 14. I was made to feel welcome and given a chance to get involved. A lot of other museums and associations I visited did NOT extend that same feeling to me.
I often hear older people at museums dismissing today's younger fans. Telling them they missed out on "real" railroading is also just as discouraging and a real insult. An oft heard refrain on a popular rail website is "It's all crap now". Well, I'm no longer in the "young" category, but that still sets my teeth on edge and I know that it really discourages younger fans. (They've told me as much.)
At Portola, some of our members have made a concerted, specific effort to attract younger fans and it is working well. What it takes is reaching out to them and making them feel wanted and included.