google it. tons of forum talk about it.
I personally have had a problem with those trying to tell us to turn railroad photography into an "art form." It's fine for them to do so, I welcome it in fact, but what I do have a problem with is that the practitioners of the more "arty" shots, I have found, tend to look down their nose's at others who are shooting more "mundane" shots.
Railroad photography is what you make of it, but one way is not "better" than another, IMHO. Unless you have a pole right thought the nose of the engine! -SG