The incident took place about 2:05 p.m. at the intersection of Mission Road and Gallardo Street, LAPD spokeswoman Officer Rosario Herrera said.
The man was in serious condition, said L.A. Fire Department spokeswoman Margaret Stewart. Paramedics transported the man to a hospital for treatment.
A desk officer at LAPD's Central Traffic Division said it wasn’t known if the man was trying to commit suicide or whether it was an accident.
“The man lost his legs when he was struck,” the desk officer said. “I know the man was seen walking around on the tracks before he was hit by the train.”
Metrolink spokesman Chris Gutierrez said the train that hit the man was leaving its maintenance yard and headed for Union Station.
“There was no one on the train when it hit the man,'' Gutierrez said. “The accident has caused delays in several trains headed to Oceanside. We think the trains will be delayed between one and two hours.''
Gutierrez said Metrolink was cooperating with law enforcement in its investigation.