As far as arresting someone for tresspass for taking photos . . . I don't know exactly how that works.
Well, Amtrak seems to be pretty notorious for harassing people with cameras. Wouldn't surprise me if some laws are made up on the spot. I think it'd hard to prove trespass if doing nothing illegal, especially if the person has purchased a ticket.
As far as the fear of trains coming off the rails, Amtrak has a bad enough record with that that I don't think the terrorists even need to intervene.
