A man fell to his death while “surfing” on top of a moving subway train Saturday morning, police said.

The doomed 32-year-old was riding the car of a southbound “J” train at Essex Street and the Williamsburg Bridge when horrified witnesses observed the man “falling from the train and getting run over” shortly after 4:30 a.m. Saturday, an NYPD spokesman said.

The unidentified victim was pronounced dead at the scene, police said. There was no criminality, the NYPD said.

J train service was suspended between Broad Street in Manhattan and Marcy Avenue in Brooklyn during the police investigation.