The discovery has led to new warnings that include Amtrak, which operates a busy route through the Central Valley.
Officials issued a bulletin warning train companies like Amtrak of the possible attack. And although evidence shows it isn't imminent, it appears Al-Qaeda had murderous aspirations that authorities are taking quite seriously.
News a potential train attack drew mixed reaction from Valley passengers at the Amtrak station in Downtown Fresno Thursday.
"Makes me a little more suspicious."
"I feel safe today. I feel real protected and covered."
Hundreds of people ride Amtrak every day to travel up and down the Central Valley.
Federal investigators learned of the possible terror plot after seizing a treasure trove of documents and computers from the compound where Osama Bin Laden was killed Sunday.
"You can't guard hundreds of miles of track. And if they can get to one location that is not well guarded and put explosives on it or do something to cause the train to derail that's a lot easier than going after an aircraft." said Former National Security official Robert Clarke.
The Department of Homeland Security says the target date was this September 11th, the tenth anniversary of the terror attacks back east.
Homeland Security spokesman Matt Chandler issued this statement saying in part, "As one option, Al-Qa'ida 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." said Chandler.
Officials wasted no time sharing the information with state and local law enforcement agencies.
"We have asked our personnel to remain vigilant. To keep an eye on things that are suspicious. Especially if it pertains to critical infrastructure. Train stations being one of those." said Fresno Police Chief Jerry Dyer.
Bertina Lankford and her husband left for San Diego on an Amtrak train hours before Bin Laden was killed Sunday. She didn't notice any extra security on her ride back home Thursday.
"No. Not a thing. The trip was the same. Going and coming back. Just long. Tiring." said Lankford.
Amtrak officials tell Action News they're always aware of potential threats but will not take any extra measures to protect passengers at this time.