A man was hospitalized Tuesday after he was smacked in the head by an oncoming train at the Penn Station subway stop Tuesday, authorities said.

The victim, 46, was waiting for a train on the Brooklyn-bound platform at the station near W. 34th St. and Seventh Ave. in Midtown about 12:50 p.m. when a No. 3 train struck him in the head as it charged out of the tunnel.

“He leaned out to look for the train, but the train found him,” said a law enforcement source with knowledge of the incident.

Medics rushed the victim to Bellevue Hospital for treatment. His name and condition were not immediately disclosed.

Trains were rerouted around Penn Station for about an hour as police investigated.