UPDATE: Sounds like the incident actually occurred near the Buena Park Metrolink station which is just past the Fullerton airport. OCFA is handling.
UPDATE 2: From the OC Register:
One person was killed after being struck by a train in Buena Park on Wednesday night, authorities said.
Crews just before 9 p.m. responded to reports of someone being struck by a Metrolink train on the tracks near Lakeknoll Drive and Dale Street, Orange County Fire Authority Capt. Marc Stone said.
One person was pronounced dead at the scene, Stone said. Authorities haven't determined the victim's gender.