This was set during the great depression or WW2. A woman is raising her kids, I think alone. They live in a shack villiage that is beside the train tracks. Her son ends up being killed by the train. One of her children gets bit by a snake and she slices it open and sucks out the poison. This is a tragic movie, but a wonderful depiction of the era it is set in.
some things don’t quite match but I’m reminded of “The Dollmaker” starring Jane Fonda.
http://www.imdb.com/title/tt0087160/
It’s at least a similar movie I can recommend.
Another “similar movie I can recommend” is The Raggedy Man, with Sissy Spacek raising two kids alone during the Depression.