Officials for Amtrak have said that the shutdown of Amtrak's Northeast (U.S.) Corridor line for a couple of hours was caused by a faulty computer response that triggered the power failure May 2006.
"The computer reduced output from one substation at a time when the system needed more power", Amtrak said.
"Other substations went into automatic shutdown because of overload, causing a cascade of power failure."
At the height of morning rush, 112 trains that included 27 Amtrak trains just suddenly stopped due to the power outage.