The southbound train hit the police car at Long Beach Boulevard and Pacific Coast Highway at around 1 p.m. The car was pushed down the tracks before the train came to a stop.
The Long Beach police officer sustained minor injuries, described as non-life-threatening. He was pinned inside his car for about 30 minutes. The officer was hospitalized along with 11 passengers.
Metro service was temporarily affected.
The cause of the incident was under investigation.