Police sources say a 14-year-old boy was injured while subway surfing on a southbound B train in Midwood.

Officers responded to the Avenue J subway station just after 4 p.m. Thursday.

A witness told News 12 that four boys were riding on top of the train when one of them fell onto the tracks.

The NYPD says the boy sustained lacerations to his head, legs and arms. EMS took him to Maimonides Medical Center in stable condition.