LA MESA, Calif. -- A bicyclist, apparently attempting to beat an approaching trolley, was seriously injured Tuesday after he rode northbound into a southbound lane and went around a trolley arm before running into the side of the trolley, La Mesa police said.

The accident shut down a busy trolley line through part of East County, authorities said.

The man hit the trolley around 5:20 p.m. near the Amaya Station, at Amaya and Severin drives, said a Heartland fire dispatcher.

The male bicyclist sustained various broken bones and was found unconscious at the scene. He was transported to the trauma center at the Sharp Memorial Hospital, according to La Mesa police.

Initial reports indicated that the cyclist was struck by the trolley, but a statement from the La Mesa Police Department makes clear that the bicyclist struck the trolley in the incident, instead.

The trolley line was closed between the Grossmont Center Station and El Cajon Transit Center, and would remain shut down for about an hour, according to Rob Schupp of the Metropolitan Transit System.

The tracks there serve the Orange Line between El Cajon and downtown, and the Green Line from Santee to Old Town.

Bus service was being arranged as an alternative, Schupp said.