"As of Feb 2010, al-Qaeda was allegedly contemplating conducting an operation against trains at an unspecified location in the United States on the 10th anniversary of Sep 11, 2001," a US official informed on May 5, though on the condition of unanimity.
The official also added, "While it is clear that there was some level of planning for this type of operation in Feb 2010, we have no recent information to indicate an active ongoing plot to target transportation and no information on possible locations or specific targets."
Giving details of the foiled al-Qaeda plan, the official said, "As one option, al-Qaeda was looking into trying 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," and also clarified, "We have no information of any imminent terrorist threat to the US rail sector."
After Osama's death, US looks determined to remove terrorism from its root. The same concern was heard from Obama when he reminded that, Osama was killed but not al-Qaeda.
The seized documents of dead Laden also hinted, as the investigating official claimed, "The US government is on to many of them."
"Other leaders of al-Qaeda should be concerned," stated the official. Now, it seems that this time US is mulling over the second bin Laden - Al-Zawahri.