Authorities say the 17-year-old girl was hanging out with her friends Friday night on the tracks beneath the 91 Freeway near Raymond Avenue.
Around 11:42 p.m., the girl was hit by the train while trying to grab her purse. The rest of the group was able to move to safety. Police believe the girl and her friends may have been drinking at the time of the incident.
Paramedics declared the girl dead at the scene. Her identity was not released pending notification of kin.
