Right, even behind the yellow line isn't always safe. The best example (an edited video of which is all over the internet) was in 1991 in the Chicago area at Downers Grove where a guy was filming the BN E9s in their last days.
The guy was filming safely behind the yellow line on the other side of the road with a tripod when a woman tried to run across the tracks at the sidewalk to beat another train; what she didn't see was the express train on the middle track, which hit her. Most versions of the video stop the split-second before she got hit.
In the unedited version you see the whole thing; she got hit, and the impact threw her body a good 100 feet or more, right into the guy with the tripod.
So always try to film from a safe location, and always keep a sharp eye out for moving objects (a loose steel band can take your head off in a second, not to mention getting hit by an unfortunate pedestrian).
