The incident occurred shortly after 1 p.m. near a tunnel along the 10300 block of N. Shadow Oaks Drive, the Los Angeles Fire Department said.
Amtrak officials said the individual was trespassing on the tracks when she was struck by Amtrak Pacific Surfliner train 767 on its way from San Diego to San Luis Obispo.
The woman was hoisted by a helicopter and transported to a hospital in unknown condition.
There were 107 people on board the Amtrak train. Amtrak officials confirmed there were no injuries to those aboard the train.
Metrolink said its Ventura County Line trains were experiencing delays due to the incident.
Update: Ventura County Line trains will experience unknown delays due to Amtrak train 767 striking a person on the tracks . We're seeking alternate transportation. Please click Train Tracker link for train location information. Updates to follow. https://t.co/a2fLDozffk— Metrolink (@Metrolink) October 18, 2018
DEVELOPING...We will add more details to this report as they become available.