It appears that it was just an accident, caused by her misjudgement- it says that it was the snowplow at the front of the train that hit her.

"Police say Tara McAvoy was walking about 2 to 3 feet from the tracks. She was on her way to her mother's business when she was hit and had just sent her mother a text message.

"McAvoy was hit by the snowplow that's attached to the front of the Union Pacific train. It sticks out a foot or two on either side."

Story