A knife-wielding maniac slashed a stranger in the face on board a Bronx train during the Friday morning rush, cops and sources said.

The victim, 27, was riding a northbound No. 2 train passing through the 225th Street station in Williamsbridge around 9:10 a.m. when an attacker sliced him with the blade, police said. 

The victim was taken to Montefiore Medical Center, where he was listed in stable condition. 

The motive for the assault is unclear, but the two men did not know each other, law enforcement sources said. 

The suspect, last seen wearing a black hoodie and navy sweatpants, fled the scene, police said. 

The attack came days after NYPD officials revealed transit crime through September edged up slightly compared to the same period last year.

“There were 15 more crimes this year than at this point last year, as an increase of 0.9 percent,” Police Commissioner Jessica Tisch said.

“In terms of major crime, the New York City subway system this year is the second lowest in 15 years, behind 2025, if you exclude the pandemic years.”

“The slight increase in major crime this year in transit is mainly concentrated in felony assault, which is up 11 percent year to date, driven in significant part by assaults against public sector workers,” she added.

Tisch also revealed that 48 percent of felony assaults in the subway system so far this year were committed by those with a documented mental health history with the NYPD – and also pointed to repeat offenders as a significant driver.