The driver of the New Jersey commuter train that crashed last week has told investigators he was fully rested but has no memory of the incident, and a recovered data recorder was not working.
The derailed train at a Hoboken station killed a 34-year-old woman on the platform and injured 108 during morning rush hour last Thursday.
National Transportation Safety Board vice-chairman Bella Dinh-Zarr said on Sunday the agency was still in the "fact-gathering phase of the investigation."
Thomas Gallagher, a 29-year veteran of the railway who was injured when the train derailed, told investigators the train was at 16km/h when it was approaching the station, Ms Dinh-Zarr said.
Investigators at this time could not ascertain the speed of the train at the time when it was near the station.