The incident occurred near the Expo/Western station, along Exposition Boulevard just west of Western Avenue around 5:30 a.m.
No trains were coming through the area at the time of the crash, and no injuries were reported.
One person was seen handcuffed and placed inside a law enforcement patrol vehicle.
Metro train service was disrupted between the Expo/Western and Expo/Crenshaw stations. Metro said buses shuttled commuters during the brief closure.
Service was delayed for about 15-20 minutes, but normal service resumed around 7:30 a.m., Metro said.
The Expo Line's newly extension between Culver City and Santa Monica was not directly impacted.
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That stretch of light rail track opened Friday, connecting the beach city to downtown Los Angeles and Metro lines stretching as far inland as suburban Azusa.