An empty commuter train slammed into a standing train at a station in suburban Chicago during Monday morning's rush hour, injuring at least 33 people, according to a Reuters report.

The out-of-service Chicago Transit Authority train barreled toward a standing train filled with commuters in Forest Park, west of Chicago just before 8am.

Nobody was driving the four-car train, which was travelling at roughly 20 mph when it hit the other train.

Injured passengers were transported to nine area hospitals. There were no serious injuries.