Osama Bin Laden's personal files

Osama Bin Laden's personal files revealed that Al Qaeda once considered attacking America's rail systems on the upcoming 10th anniversary of 9/11.

A document dated February 2010 shows the terrorists wanted to "tip a train by tampering with the rails so that the train would fall off the track at either a valley or a bridge," a federal bulletin said.

Since 2001, Al Qaeda cells have successfully targeted subways and trains in Spain, Britain and India, spreading carnage among commuters.

Officials stressed they had no evidence the anniversary transit plot ever went beyond dreaming of derailing an American train this summer.

"As far as we can tell, it didn't even get into the planning stages," a law enforcement source said. "There is no evidence so far that this plot was approved or moved further."

Nevertheless, the FBI and Homeland Security asked local authorities to watch train tracks for missing "clips or spokes" and "concrete blocks or tree limbs placed on tracks."

"We have no information of any imminent terrorist threat," said Department of Homeland Security spokesman Matt Chandler, "but wanted to make our partners aware of the alleged plotting."

Chandler said the department did not plan to issue a National Terrorism Advisory System alert - the new system that replaced the Bush-era color-coded terror level chart.

The U.S. commandos who killed Bin Laden in Pakistan on Sunday snatched a treasure trove of computers, disks and hard drives from the terror leader's compound.

The material contained possible leads on the whereabouts of other Al Qaeda leaders - even strengthening the hunt for the terror group's No. 2 man, Ayman al-Zawahiri, The Washington Post reported.

"We have lots of information on him," Rep. Mike Rogers (R-Mich.), chairman of the House intelligence committee, told the newspaper. "I can't say it's imminent, but I do believe we're hot on the trail."

One source told The News the train plot was found in handwritten notes, not the computer files.

"That this kind of 'brainstorming' idea was among Bin Laden's materials indicates he may have been more involved in the operational debate than many thought," a law enforcement source said.

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