I would suspect that well over half of these deaths are suicides. How can a person, 1.) Not hear the train coming, and 2.) not look up and see a train coming before they step across RR tracks? Seems unfathomable without severe intoxication or a death wish.
But the state of mind of the deceased at the time of death can be difficult to prove, and relatives may not want to believe the person actually killed themselves, so they might prefer to believe it was an accident, and may even sue the railroad on the theory it was an accident. Or maybe they know the person killed themselves, but are trying to squeeze some money out of the RR.
I'm telling you though, if I was on a jury of one of these cases, I would have a very difficult time believing the RR had any fault when someone steps into the path of an oncoming train, with three blinding headlights, no ability to steer, and whose horn can be easily heard from 5 miles away.