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.

Inspectors have found small, sub-surface cracks in two more Southwest Airlines planes which are similar to those that caused a jet to lose pressure and make a terrifying emergency landing in Arizona, the airline said today.

US investigators removed data recorders from a train that derailed and burst into flames over a bridge in south-western Pennsylvania as ethanol tanker carriages continued to burn today.