Passenger who survived New York train crash intends to sue railroad (Dec. 4, 2013; CNN.com)

(CNN) -- A passenger on the Metro-North train that derailed Sunday in New York has filed a notice of claim against the commuter railroad -- an initial step in a lawsuit seeking unspecified damages in connection with the accident, which killed four people and injured 67 others.

Attorney Michael Lamonsoff said Wednesday that the suit on behalf of Denise Williams, a retired Army colonel and dentist who was on her way to a convention at the time of the crash, will accuse the commuter railroad of negligence. He said state law requires that negligence claims be filed against the railroad, not the train engineer, who allegedly nodded off as the train was speeding into a sharp curve. The Metropolitan Transportation Authority declined to comment.

"Bottom line is the guy was going 82 mph in a 30 mph zone," said Lamonsoff, adding that the railroad has been slow to implement what is known as positive train control technology, which combines GPS, wireless radio and computers to monitor trains and stop them from colliding or derailing. In 2008, Congress ordered rail lines to adopt the technology by December 2015.

"We have GPS on cars, they should have GPS on the trains, he said. "They have been stonewalling, they have until 2015, they have asked for extensions, they haven't started any upgrades."

MTA spokesman Salvatore Arena said the agency began work to install positive train control on the Long Island Rail Road and Metro-North Railroad in 2009, budgeting nearly $600 million for its installation, including $428 million last month for a system integrator. The cost for full implementation is estimated at $900 million. But, Arena said in a statement, implementing it by the 2015 deadline will be difficult because much of the technology is still under development, untested and unproven on commuter railroads the size of Metro-North and LIRR.

National Transportation Safety Board member Earl Weener said Tuesday it's possible that positive train control could have prevented a derailment involving a high-speed train, such as the one involved in the Metro-North accident.

Lamonsoff said his client suffered spine, collarbone and rib fractures after she was pinned inside an overturned car for about an hour.

"While she was ... pinned down, there was a guy that, a chef who has cerebral palsy, he sat with her and prayed with her because they didn't know if she would live or die and she was praying to live," Lamonsoff said.

Train union kicked out of crash investigation

The NTSB, meanwhile, has booted the rail union from its investigation into the deadly train derailment for violating confidentiality rules.

The agency made the announcement late Tuesday night, hours after a union representative told CNN that the train engineer apparently "was nodding off and caught himself too late" before the accident.

In its announcement, the NTSB specifically cited those comments as the violation.

Anthony Bottalico, the union representative, told CNN that engineer William Rockefeller Jr. recognizes his responsibility in the incident.

"I think most people are leaning towards human error," Bottalico said.

Rockefeller's lawyer, Jeffrey Chartier, characterized what happened as "highway hypnosis." He said his client had had a full night's sleep before the crash and had no disciplinary record.

In a brief conversation with investigators, Rockefeller said that moments before the derailment of the Hudson Line train in the Bronx, he was "going along, and I'm in a daze. I don't know what happened," according to a law enforcement official familiar with that conversation.

Rockefeller spoke to Metropolitan Transportation Authority and New York police detectives at the crash site before he was taken to a hospital Sunday.

According to NTSB representatives, results from alcohol breath tests for the train engineer were negative, and the brake and signal systems in the deadly Metro-North accident appeared to be working. Other toxicology results have not yet come back.

Fatigue is a factor being investigated, according to a separate New York law enforcement source. But Rockefeller also told investigators on site that the brakes had failed, as CNN reported previously. Officials noted that the train had been able to stop nine times at stations before the crash.

The train was equipped with a "dead man's pedal," designed to stop the train if the engineer becomes incapacitated, said Weener, the National Transportation Safety Board member. But it was unclear whether that emergency system was activated.

Feds: Metro-North train accidents 'unacceptable'

Expert: 'Twilight' common among some train crews

Steven Harrod, a University of Dayton professor and expert on railway operations, said the early hour of the derailment, along with the decreased rail traffic on the post-Thanksgiving weekend, also could have played a role in Rockefeller's "daze."

Harrod called it a "twilight" of inattention or distraction common in transport crews on late-night and early-morning shifts.

"If he was dead, dead asleep, his hands would have come off the controls and ... some of the 'dead man' stuff would have come into play," said Harrod, referring to "dead man" mechanisms that automatically stop trains when the engineer is incapacitated. "But if it was kind of that twilight where you're just there and still kind of gently holding on to things but not quite really aware, which in my mind is still sleeping. That's still sleeping."

In the culture of railroad workers, Harrod said, admitting to falling asleep at the controls is almost as bad as admitting to being drunk or on drugs.

"It's very realistic that he, in fact, really did fall asleep," he said. "Falling asleep at the controls of a locomotive is a horrible evil. You're not supposed to do that. He really doesn't want to come out and say, 'I fell asleep.' It's emotionally embarrassing. It's not just a rules violation. There's a psychological component. If you come out and say, 'I fell asleep,' it's just purely beyond embarrassing. It's a violation of the sacred understanding of what a train crew should do."

Rockefeller is not working or getting paid, said Meredith Daniels, an MTA spokeswoman.

"He is out of service. This is an unpaid status," said Daniels, adding that Rockefeller is presumed innocent until disciplinary procedures are completed.

NTSB officials would not comment on Rockefeller's reported comments, but they have said fatigue is routinely investigated as a possible cause in such cases.

Harrod said the rail and signal hardware date to World War II and, if Rockefeller was dazed or momentarily distracted, there was no system in place to alert him that he was traveling at 82 mph.

"It's a perfect-storm kind of thing," he said. "You can look back in the history books of railroad accidents and there are plenty more where this came from. Events and things that happen that in and of themselves are not supposed to be bad but they turn into bad things."

Opinion: Can high technology make trains safer?

Engineer cooperating with authorities

The train was about 10 miles short of its destination, Manhattan's Grand Central Terminal, when it derailed on the approach to the Spuyten Duyvil station in the Bronx.

The NTSB's interview Monday with Rockefeller was cut short because of his emotional state, Weener told CNN. The interview resumed Tuesday and was expected to continue Wednesday.

"I think it was basically emotional issues with the engineer," Weener said. The crash, which took four lives, was "a very traumatic experience for him." Weener said Rockefeller was cooperative but was "not up to it."

NTSB officials said it is not unusual for those who have survived fatal accidents to be emotional during interviews. Nor is it unusual for the board to allow participants additional time to complete the interview.

Bottalico said Rockefeller is cooperating.

"Billy is fully cooperating with the NTSB," Bottalico said. "He needed to get some rest. He's very traumatized by the loss of life. It's best that it comes from him what happened. He's a quality human being. I know him personally. I've been a conductor and representative, and I'd be proud to have him as my engineer."

Rockefeller started out as a janitor at Grand Central and "worked his way up," Bottalico said.

"He's been in operations for quite a while," he said. "He used to change the time of the trains in Grand Central. He was volunteer fireman. He's just a guy who's always gone out of his way for everyone else. It brings me to tears because the loss of life is something that -- it's the hardest thing to deal with. When you lose life, it's difficult for all."

Said Harrod, the railway operations expert: "This engineer, I'm sure, as the evidence comes out, I think we're really looking at a sad, really basic kind of inattentiveness. Nothing fancy: No alcohol, no drugs, maybe not even a cell phone. Just plain vanilla inattentiveness."

Michael McClendon, who supervised engineer Rockefeller for several years, spoke to CNN affiliate WCBS.

"I wish this didn't happen to anyone, but I sure as hell don't want it to happen to him," he said.

Living through a train wreck

CNN's Allison Malloy, Mike Ahlers and Ross Levitt contributed to this report.

Train crash investigation focuses on engineer