The individual was hit at the Arlington Park Metra station, which is located just outside the racecourse, about 7:20 a.m. Arlington Heights police said Wilke Road was closed at Northwest Highway just before 8 a.m., as a result of the incident.
Arlington Heights fire officials said the person died on the scene.
Arlington Heights is along Metra's Union Pacific Northwest line. The commuter rail tweeted that riders should expect extensive delays.
UP-NW trains resumed with delays about 8:30 a.m., Metra said. But trains would not stop at the Arlington Park station.
The Cook County Medical Examiner's Office did not immediately release details about the death Tuesday.
Sun-Times Media contributed to this report.