On weekends every other train out of O'Hare ends at UIC because there is more ridership between there and O'Hare than the entire route. On weekdays select trains also end at UIC for the same reason.
UIC stands for University of Illinois at Chicago, which is on the route towards Forest Park but has a track to turn trains around after the platform. On weekends (when I filmed this) every other train that departs O’Hare short turns at UIC instead of doing the whole route to Forest Park.
@@MetxsightseerRailfan University of Illinois at Chicago is the main attraction since you can see it from the platform, but the station is called Halsted
Some other terminals also have departure bells. Harlem on the Green Line and Midway on the Orange Line do, along with a green light that lights up by the operator on the departure track when the bell dings.