Wednesday, June 24, 2009

Metro Transit Crash: Invisible Hand on the Throttle

Tue Jun 23

WASHINGTON – Investigators looking into the deadly crash of two Metro transit trains focused Tuesday on why a computerized system failed to halt an oncoming train, and why the train failed to stop even though the emergency brake was pressed.

At the time of the crash, the train was also operating in automatic mode, meaning it was controlled primarily by computer. In that mode, the operator's main job is to open and close the doors and respond in case of an emergency.

Debbie Hersman, an investigator with the National Transportation Safety Board, said it was unclear if the emergency brake was actually engaged when Monday's crash occurred. But the mushroom-shaped button that activates it was found pushed down in the operator's compartment.

The train plowed into a stopped train ahead of it at the height of the Monday evening rush hour, killing nine people and injuring more than 70. It was the deadliest accident in the 30-year history of the Metro.

Crews spent Tuesday pulling apart the trains' wreckage and searching for victims' bodies. And authorities worked to determine why the train's safeguards apparently did not kick in.

"That train was never supposed to get closer than 1,200 feet, period," said Jackie Jeter, president of a union that represents Metro workers.

On Tuesday, all Metro trains were running on manual control as a precaution against computer malfunction. ...

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