No we'll never know. It's possible, that it was a simple lapse. She might have been preoccupied, or so familiar with the crossing which she'd crossed dozens of times, that she simply didn't think.

I wouldn't be blaming her at all, except to counter those who insist that poor design or some factor other than the victim was at fault. Stuff happens, people make mistakes, and sometimes there's no one to blame except to say that someone suffered a severe penalty for a minor lapse.

BTW- be honest with yourself. How many times have you crossed a pair of railroad tracks without stopping and looking? I lost count decades ago. I'd like to believe it's not just luck and I'd have been aware enough if there were a train, but who knows.