NEW YORK — A New York City subway train derailed Tuesday as it entered a station in Harlem, tossing people to the floor, forcing hundreds of shaken-up passengers to evacuate through darkened tunnels and delivering another jolt to a transit system plagued by aging equipment and reliability problems.

Nearly three dozen people suffered minor injuries in the derailment, which happened just before 10 a.m.

Photos of the train posted on social media showed its metal side deeply scraped and dented from being dragged along the wall of the subway tunnel. Debris, including broken signaling equipment and chunks of concrete, were left in the train’s wake.

Passengers on the A train said it suddenly jerked and began shaking violently as it approached the station at 125th Street and St. Nicholas Avenue.