The conductor of the Union Pacific train told authorities that Melinda Champion was talking on her phone when the train hit her from behind on Wednesday.
The train was headed south near Anderson, a town in far north-central California. A police sergeant said the conductor applied the emergency brakes when he spotted the woman, who apparently did not hear the train's whistle or feel the vibrations on the tracks.
The train struck her at about 45 mph, bouncing her to the side of the tracks.
Police Sgt. Bob Curato told The Associated Press on Thursday that Champion was recovering at a local hospital, but her condition was not available.