Several people have posted concerns about a lack of volunteerism when it comes to rail preservation. One of the wonderful things about the Friends of the C&TS (shameless plug here) is the excellent quantity and quality of volunteers this organization enjoys.
Still, the concern raised about volunteerism (and not just on railroad ventures) is valid. I am involved with several other volunteer organizations (non-rail) and the problems are the same there. There are fewer volunteers and they are tending to become and older group. I'm always amazed how gung-ho some potential volunteers are until they find out that they are actually expected to work--then they disappear.
How to involve and energize future volunteers will be a continual challenge for all volunteer organizations. It's too bad that many people don't know how wonderful volunteering is. Some of the best times of my life and some of the best friends I've met have come from my volunteer activities. What more reward can one ask for than that?