Chicago Blue Line train derails during rush hour

A CTA train derailed Wednesday on the Blue Line, causing major disruption on a key commuter artery at morning rush hour.

Heavy rains slowed the commute by vehicle on Chicago's expressways, and a downed tree blocked another major commuter rail line in the northern suburb of Kenilworth, disrupting service on Metra's Union Pacific-North Line.

The Blue Line derailment occurred around 7:15 a.m. near the Pulaski station along the Forest Park branch on the city's West Side. No injuries were reported.

A wheel on one of the inbound train's cars partially slipped off the track, but there was no immediate information on a possible cause, said CTA spokeswoman Tammy Chase.

The Chicago Fire Department helped passengers out of the affected car.

Passengers on the other Blue Line branch, between downtown and O'Hare International Airport, might also encounter residual delays as a result, the agency said.

Transit authorities described the accident as minor and said service was halted between four stations near the derailment. Shuttle buses carried commuters around that area.