A woman was fatally struck by a Harlem train early Saturday, cops said.

The victim, believed to be in her 30s, was on the tracks when she was struck by the No. 3 train at 125th Street and Lexington Avenue at 8:20 a.m., authorities said.

She was on the tracks about 200 feet north of the station on the southbound side, MTA sources said.

It is not yet known if there’s any criminality but transit police were on scene investigating.

The identity of the deceased is pending proper family notification.