CTA probing operator error in derailment

A preliminary Chicago Transit Authority investigation suggests that operator error played a role in the derailment of a southbound Green Line train this morning that injured 14 people.

The accident, which occurred over 59th street between Prairie and Calumet, sent two of the train's four cars off the rails.

Two dozen passengers were on board. Ten declined medical treatment and none of the others were seriously injured, according to the Chicago Fire Department.

The accident occurred at a junction where the Green Line's southbound tracks diverge. One branch heads toward 63rd and Cottage Grove; the other goes to 63rd and Ashland.

A safety recorder shows the operator of the Cottage Grove-bound train went through a red signal before reaching the junction, says CTA chief Ron Huberman.

At the junction, the train hit a mis-positioned switch that may have forced it off the rails.

A backup system brings trains to a stop when an operator ignores a stop signal. It's unclear whether that system stopped the train, or  if the operator reset the system and continued on, Huberman says.

The switches in question were refurbished in 1996, though some of the parts in that section of the track are over 35 years old.

Late this afternoon, the Green Line south of the Garfield station remained closed as the crash investigation continued.

The CTA is using buses to shuttle those passengers from there to the Cottage Grove and Ashland stops.