The man, who can be seen in police photos released Sunday, grabbed the 26-year-old woman by the arm on the staircase of the station about 2:30 a.m. Oct. 30, police said.
She resisted him and he fled, police said.
She later realized that he'd robbed her, police said.
The suspect hadn't been arrested as of Monday morning, police said.
Anyone with information should contact Crime Stoppers at (800) 577-TIPS (8477).