Could the location of an early-alert system prevented Sunday's deadly train derailment in the Bronx?
That's the question being raised as the investigation into Sunday's Metro-North crash continues.
Metro-North confirmed that an "alerter" system was installed in the rear locomotive of the train.
The system is designed to automatically sound off after 25 seconds and applies the brakes if there is no response from the engineer within 15 seconds.
However, William Rockefeller was driving the train from a cab in the front, where there was no alerter system.
Union reps say Rockefeller was in a daze when the train reached a curve at 82 miles per hour, instead the posted 30.
Investigators say Rockefeller hit the brakes too late at that point and the train went off the tracks, killing four people and injuring dozens more, including 11 critically.
A former co-worker said the veteran engineer was having a tough time adjusting to his new early-morning shift. He said Rockefeller made subtle comments that he liked afternoon shifts better.
"We shouldn't assume that that's going to be easy. That people can naturally shift from days to nights to evenings or whatever shift is necessary,” said Dr. Steven Feinsilver of Mt. Sinai Center for Sleep Medicine.
Rockefeller was hurt in the accident. He has been placed on unpaid leave.