Yesterday at 8 a.m., an unmanned train slammed into another at a suburban Chicago station on the west end of the Blue Line, causing injuries to four dozen passengers.

Authorities and investigators, alike, have failed to find the explanation behind the empty, wandering 4-car train, and how it met the forty-passenger, 8-car train parked at the Harlem Avenue stop in Forest Park, IL. Baffled and claiming a "very strong safety record," the CTA is calling what happened a mystery.

The "ghost" train travelled half-a-mile east before colliding into the westbound train. The CTA supervisor at the station tried to contact the moving train as it approached, but found it unresponsive. He then told the first car of passengers to brace themselves.

The train did not halt despite fail-safes set in place (levers, switches, etc.) to stop anything of this nature from happening... though it has never happened before.

Amalgamated Transit Union President, Robert Kelly said that he's never heard of an unprompted train rolling down the tracks. In fact, it should be impossible considering that it takes two special keys in order to access and start the train.

"In order for a train to move, it has to be energized," said Ronald Ester, vice president of CTA Rail Operations.

Kelly urges admission from anyone who might be withholding evidence. He's rightly concerned that if this was a train that decided to move on its own, then it is possible that it may happen again.

CTA spokesperson Brian Steele said that National Transportation Safety Board is investigating and examining signaling systems, data, and the platform video feeds that recorded the event.

Fourty-eight passengers were injured, and thirty-three of those individuals were transported to ten hospitals throughout the area. The greatest complaint was neck and back pains, but these injuries are believed to be minor.