A 42-year-old woman was stabbed by another woman in an unprovoked attack inside the Intervale Avenue subway station in Longwood, according to police.

The NYPD says the victim noticed a woman acting erratically on the northbound platform just before 6 p.m. Friday.

According to investigators, that woman then walked up to the 42-year-old and stabbed her in the arm.

Paramedics took the victim to Lincoln Hospital, where police say she is expected to recover.

Her alleged attacker remains on the run as of Saturday evening.