Documents seized from Osama bin Laden's compound show that al-Qaeda was debating a plan to target an American train on the tenth anniversary of the 9/11 attacks.
As Amtrak marks its 40th anniversary with a "National Train Day" event, new details are emerging about al-Qaeda's latest plan to attack U.S. Railways.
Starting in February 2010, Al Qaeda reportedly discussed tampering with train tracks at a valley or a bridge.
Counterterrorism officials say they believe the derailment plot was only in the initial planning stages, and there is no recent intelligence to suggest any active plan.
But the FBI and Homeland Security still issued an intelligence bulletin to local law enforcement.
And amtrak officials are promising "increased vigilance."
The FBI has told local officials to be on the lookout for clips or spikes missing from train tracks, or packages left on or near the tracks.
Homeland Security officials say "this alleged plot is based on initial reporting which could be inaccurate and subject to change."
They say they have no plans to issue an official terror alert because of it.
ABC7's Mike Conneen reports from Union Station and gets reactions from Amtrak riders.