The outbound train #2103 struck the person around 8:10 a.m. between the Libertyville station and Winchester Road, according to Metra spokesman Michael Gillis.
The accident caused extensive delays during the morning rush.
The age and name of the victim have not yet been released.
The circumstances surrounding the incident are still being investigating.
Both the Lake County Coroner's office and Libertyville Police Department are investigating.