Federal investigators have determined that an Amtrak train that crashed in Philadelphia, killing at least eight people, was careening through the city at 170km/h before it ran off the rails along a sharp curve where the speed limit drops to just 80km/h, yet they still don’t know why it was going so fast.

The engineer in a deadly train derailment in Philadelphia does not remember the crash, his lawyer said, complicating the investigation into why the Amtrak passenger train was going more than twice the allowed speed when it shot off a sharp curve.

Irene has weakened to a tropical storm as it raced across New York City, leaving behind a stunned east coast where at least nine people died, severe flooding was widespread and four million homes were without power.

A weakened but still dangerous Hurricane Irene slammed into the New Jersey shore with 75mph winds today after dumping a foot of rain on North Carolina and Virginia, killing nine people and knocking out power to at least two million homes.

A weakened but still dangerous Hurricane Irene slammed into the New Jersey shore with 75mph winds today after dumping a foot of rain on North Carolina and Virginia, killing eight people and knocking out power to at least two million homes.