Caught on camera: shocking video showing the moment a woman faints, falling head first onto train tracks.
An off-duty police officer jumped into action moments before a train arrived at the station.
People on the platform were able to get the conductor's attention and the train stopped just in time.
The officer, with the help of fellow commuters, pulled the 52-year-old woman to safety.
A doctor at the scene checked out the woman, who is expected to be okay -- just a little shaken up.