The shooting happened around 10:45 p.m. at the Garfield Station, which is in the median of the Dan Ryan Expressway.
[Ads /]
A witness told police that a man pulled a knife during an argument, and another man pulled a gun and fired shots.
The victim who was shot was hospitalized, initially reported to be in fair condition.
Police continue to look for the shooter.
[Ads /]
After an overnight shutdown, Red Line service was restored Sunday morning, the CTA said.
No further information was immediately available.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood