An unhinged man slashed three strangers in a string of unprovoked attacks that began on a Queens train, cops and police sources said.

The emotionally disturbed man pulled out a straight-edge razor and randomly slashed a 45-year-old straphanger in his left ear and arm at about 8:20 a.m. on a Jamaica Center-Parsons/Archer station bound E train to begin his spree, police said.

The slasher got off the train at the Queens Plaza subway station in Long Island City and went to the street where he struck again, slicing a 23-year-old man in the left side of his face, and a 32-year-old man across the right side of his face on 27th St. near 43rd Ave., cops said.

Medics rushed the 23-year-old man to NewYork-Presbyterian Weill Medical Center, and the 32-year-old man to NYC Health+Hospitals Elmhurst. The 45-year-old man went to NYC Health + Hospitals/Queens by private means. All three men were in stable condition, cops said.

Medics also took the slasher to NYC Health+Hospitals Elmhurst to undergo a psychological evaluation, police said. Charges were still pending for him on Saturday afternoon.

The Saturday morning slashings came less than 24 hours after 40-year-old Johnny Medina was brutally stabbed to death inside the 175th St. A train subway station in Washington Heights. Cops arrested 24-year-old Diego Figueroa-Hepner for the slaying Saturday and charged him with murder and weapons possession.