It happened around 10 p.m. on the stairway of the PATCO high-speed line at 15th and Locust streets.
Police say a man in his 30s was rushed to an area hospital after being stabbed 11 times. He is currently listed in critical condition.
SEE ALSO: Man stabbed inside Wawa in Philadelphia's Mount Airy neighborhood
It's still unclear what sparked the attack.
No arrests have been made.
Anyone with any information is asked to call police at 215-686-TIPS.
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