“Many of those times you were asleep. You’re just not going to remember it,” he said.
Transportation safety advocates also have long been concerned about fatigue in all modes of transportation.
In 2008, the operator of a transit train was killed after she fell into a micro-sleep and collided with another train in Newton, Mass. Fatigue also was a factor when two trains collided in Red Oak, Iowa, in 2011, killing two crew members.
A survey of transportation workers last year by the National Sleep Foundation found 26 percent of train operators said sleepiness affected their job performance at least once a week, compared with only 17 percent of non-transportation workers. About 18 percent of train operators reported having a “near miss” at work because of fatigue, and 44 percent of train operators said their work schedule did not allow enough time for sleep.
Rockefeller’s schedule, which had recently switched from the afternoon shift to the day shift, could be a cause for concern about fatigue, said Patrick Sherry, executive director of the National Center for Intermodal Transportation at the University of Denver, which studies national transportation issues.
“Did he make an appropriate transition from his previous shift to this new shift?” Sherry said.
How long that transition takes is highly individual — think jet lag, which levels some people while others adjust easily, said Dr. Clete Kushida, a neurologist and sleep specialist at Stanford University Medical Center.
Federal investigators would not comment on Rockefeller’s level of alertness. The NTSB had found no problems with the brakes or rail signals. Alcohol tests on crew members were negative, and investigators are awaiting the results of drug tests.
The NTSB has issued more than 200 recommendations addressing fatigue, including scheduling problems that disrupt sleep patterns, Chairman Deborah Hersman said Wednesday in a telephone interview.
Hersman said positive train control technology, which can slow or stop a train that’s speeding or otherwise not being operated correctly, might have forestalled the derailment. Railroads are facing a congressional deadline to install such systems by December 2015.