It happened around 2:10 p.m. on the northbound platform at the Chambers Street A/C station in Tribeca.
The victim was taken to Bellevue Hospital in serious but stable condition. His injuries are not thought to be life threatening.
The suspect fled on a northbound train.
No arrests were immediately made, and there no word on the circumstances that led to the stabbing.
A and C trains were bypassing Chambers Street in both directions for the police investigation.
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