"Billy is a very sincere guy. This is a man who is totally distraught by the loss of life, and he's having a tough time dealing with that," said Bottalico, the general chairman of the Association of Commuter Rail Employees.
Rockefeller, 46, has been an engineer for about 11 years and a Metro-North employee for about 20, he said.
Positive train control, or PTC, is designed to forestall the human errors that cause about 40 percent of train accidents. The transportation safety board has urged railroads to install PTC in some form since 1970, and after a 2005 head-on collision killed 25 people near Los Angeles, Congress in 2008 ordered rail lines to adopt the technology by December 2015.
Grady Cothen, a former FRA safety official, said a PTC system would have prevented Sunday's crash if the brakes were working normally. And Steve Ditmeyer, a former FRA official who teaches at Michigan State University, said the technology would have monitored the brakes and would not have allowed the train to exceed the speed limit.
"A properly installed PTC system would have prevented this train from crashing," he said. "If the engineer would not have taken control of slowing the train down, the PTC system would have."
The Metropolitan Transportation Authority, which runs Metro-North, began planning for a PTC system as soon as the law was put into effect, spokeswoman Marjorie Anders said. After some early-stage work such as buying radio frequencies, the MTA awarded $428 million in contracts in September to develop the system for Metro-North and its sister Long Island Rail Road.
But the MTA has advocated for an extension to 2018, saying it's difficult to install such a system across more than 1,000 rail cars and 1,200 miles of track.
"It's not a simple, off-the-shelf solution," Anders said Monday.
On Sunday, the train was about half full, with about 150 people aboard, when it ran off the rails while rounding a bend where the Harlem and Hudson rivers meet. The lead car landed inches from the water.