A 33-year-old woman was killed when she fainted and fell in front of an oncoming train in an Upper West Side subway station Saturday morning, according to cops and the MTA.

The unidentified woman passed out onto the tracks at the 72nd Street station around 10:30 a.m., and was struck by a northbound 3 train, an MTA spokesman said.

The woman was taken to Mount Sinai St. Luke’s Hospital, where she was pronounced dead, cops said.