Rails & Ties (2007) on Netflix

Plot summary

Laura Danner, a single mother with mental illness and drug use, cannot care for her ten-year-old son Davey. She drives onto a railroad track with him, intending to die. Davey spits out the tranquilizers she gives him and tries to drag her from the car before jumping clear as a train approaches. His mother is killed. The train's engineer, Tom Stark, and Otis Higgs argue over whether an emergency stop would derail the train. The railroad suspends both men pending an inquiry. Davey spends his first night after the crash with a social worker, Renee, who then places him with a disciplinarian foster mother.