About 5:56 a.m. police received "some type of hand-scribbled note" indicating there was a bomb at the station, said police News Affairs Officer John Mirabelli.
Chopper7HD was first on the scene showing street closures in the area. Heavy police activity was spotted shortly after 6:30 a.m. Bomb-sniffing dogs were also on the scene.
Initially, no pedestrians were getting into the station at Ravenswood and Greenlee, and vehicular traffic on the east-west streets also was not getting underneath the railroad tracks.
Trains began moving again after 7 a.m. and police reopened the station after authorities found a pizza box and determined there was no threat.
(The Sun-Times Media Wire contributed to this report.)