A woman was arrested in the fatal stabbing of a straphanger at a Brooklyn subway station, law enforcement sources told The Post Tuesday.

Mia Simmons, 20, was arrested on charges of manslaughter and criminal possession of a weapon for the brutal attack, cops said.

Sources said the suspect cut her own hand during the attack, leaving behind a trail of blood.

The victim, identified as 30-year-old Latanya Watson, was in the mezzanine of the Sutter Avenue-Rutland Road train station off the No. 3 line in Brownsville Monday night when she got into a fight with another woman, police said.

Simmons knifed the victim multiple times in the face, neck and arm, cops said.

Medics rushed Watson, who lived less than a half-mile from the train station, to Brookdale Hospital, but she could not be saved.

It was not immediately clear what the dispute between the Simmons and the Watson was over.