The fatal derailment of an Amtrak train south of Seattle on Monday is likely to intensify scrutiny of the national passenger railroad company's safety record, which was already under the microscope following a series of fatal incidents.

The U.S. National Transportation Safety Board (NTSB) said late on Monday that a data recorder retrieved from the rear locomotive showed the train was traveling at 80 miles (130 km) an hour in a 30-mile-per hour zone when it jumped the tracks.

The NTSB said it was too soon to say if that contributed to the crash, which killed at least three people, and it could take months for the board's investigators to reach a conclusion.

Amtrak's co-chief executive, Richard Anderson, told reporters earlier on Monday he would not speculate on the cause of the crash, and that safety was the firm's top priority. But he acknowledged that positive train control (PTC), a system that automatically slows trains if they are going too fast, had not been installed on that stretch of track.

Just last month, the NTSB chairman issued a scathing critique of Amtrak's culture, saying a future breakdown was likely, and the board made nine safety recommendations.

"Amtrak's safety culture is failing and is primed to fail again, until and unless Amtrak changes the way it practices safety management," Robert Sumwalt said on Nov. 14.

Sumwalt's statement was made in conjunction with the NTSB's findings into a fatal Amtrak accident in April 2016 in Pennsylvania, which it said was caused by "deficient safety management across many levels of Amtrak and the resultant lack of a clear, consistent and accepted vision for safety."In that crash an Amtrak train struck a backhoe tractor on railroad tracks in Chester, Pennsylvania, killing two maintenance workers and injuring 41. It occurred a few miles south of the site of a May 2015 derailment in which eight people were killed and more than 200 injured.