He was taken into custody, authorities said, but police are still looking for a female passenger and were sending canine units into the tunnel to help with the search.
Before ending up on the tracks, the man led police on a wild high-speed chase through East L.A., sometimes driving on the wrong side of the road and even onto sidewalks.
He nearly hit at least one pedestrian and T-boned a taxi before driving into the underground Metro tunnel in Boyle Heights.
The investigation is ongoing.