The theft was reported at 10 p.m. at the station at 3401 E. 12th St.
Police said the victim was trying to process his ticket to pay for his ride when the suspect punched him in the head and took his wallet.
The suspect ran from station and may have been with another person who did not play a part in the robbery.
Police described the suspect as black, 5 feet 10 inches tall wearing a black hat, black jacket, and jeans. He also had a small pit bull with him, police said.