Authorities are on high alert after an apparent sabotage of train tracks in Iowa.

The FBI is investigating the case, trying to find out who tampered with a switch box near Menlo, Iowa. The trains that cross those tracks carry ethanol, which is highly flamable and can burn for long periods of time.

Trains were able to successfully cross the damaged tracks, but the crew noticed that something was wrong and reported the incident to the Iowa railroad.

Doris Harwood's home is right next to the switching station that was sabotaged, and the incident makes her uncomfortable.

"I have been here 20 some years and never had anything like this happen," Harwood said.

Although officials don't believe terrorism is involved, Amtrak has raised the security alert for its passenger trains nationwide.

During the recent raid in Pakistan that killed Osama Bin Laden, the Navy SEALs found evidence that Bin Laden had urged Al Qaeda followers to derail U.S. Trains on the 10th Anniversary of September 11th.

Amtrak's Chief of Police, John O'Connor, says that those threats are cause for concern.

"The recent events after the death of Bin Laden serve as a stark reminder that these threats continue to be viable, and that a new twist was added--that terrorists are considering derailing trains," said O'Connor in a recent meeting with a senate committee.

Amtrak started new security measures Tuesday. They'll be most visible in the heavily traveled Northeast corridor between Boston and Washington.

"Training our employees in how to spot suspicious behavior and activity and also layerin in random screening of bags (and) canines, both in the stations and on board the trains," explained O'Connor.

Amtrak will have to secure more than 20,000 miles of tracks across the nation.