People watch too many silly TV shows that depict photography as a prelude to criminal or terrorist action, so when they see a rail buff with his camera they lose their minds.
I went to South Korea for three weeks last year, rode trains nearly every day and took hundreds of pictures, a great many of which were at train stations. No one paid any attention to me and no one called the cops on this high-nose western foreign devil. (While some Asian countries refer to westerners as round-eyes, in Korea we're known as "high noses" because the bridge of a westerner's nose is higher than that of a typical Korean.) Mind you, North Korea, a very unpleasant place, is right next door, but no one saw any reason to think a harmless rail fan/tourist was anything but a harmless rail fan/tourist. My own country, however, is a 3,000-mile-wide loony bin, and every time I take a train picture I wonder if someone who sees me is dailing 9-1-1.