While I very much dislike the title "foamer", I am certainly a railfan - otherwise why bother? On the other hand, I would stress that when you are crew, training or otherwise, that is what you have to keep your mind on.
As a general rule, I can't fathom a crew member carrying a camera. Not that it would be a hard and fast rule, but the only reason I would do it would be because I had to carry it as luggage.....
I worked extensivly in mechanized farming ,to a very limted extend in logging, and a fair amount of trolly/interurban operation. You can't be distracted with stars in your eyes. Besides, the work should be it's own reward. When I come on as a crew member I come to work. Period.
This can be a problem with railfans and/or people who have never really worked around machinery (office types). Not to say those folks shouldn't try out for crew but it just means that they have more to learn.
My first full day as a crew member on the Sumpter Valley was largely spent operating the Plymouth 12 ton as a trainee and I loved every clanking jarring minute of it. (it was more fun than the 55 ton BC interurban I used to run) As to my performance, that's for others to judge. (Remember I didn't blow up the speeder that day.......)
Lon