The shooting took place at about 4:15 a.m. near a CTA facility in the 9900-block of South State Street.
Police said the man was found with a gunshot wound to the chest and transported to Advocate Christ Hospital in critical condition. He was later pronounced dead, police said.
A CTA spokesperson said they were alerted to a disturbance outside a maintenance shop.
Further details were not immediately available. Area Two detectives are investigating.
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