New York (CNN) -- Details started to trickle out Tuesday about the engineer at the center of Sunday's New York train derailment.
William Rockefeller Jr., or Billy, has worked as a locomotive engineer for almost 11 years, according to Anthony Bottalico, a union representative who has been meeting with the man.
He said Rockefeller started out as a janitor at Grand Central and "worked his way up."
"He's a man of a lot of character. He's honest. He's sincere. He's never been disciplined, that I know of, on the railroad," said Bottalico. "He's got a great attitude and he comes to work every day, and everybody's very proud and honored to work with him."
The representative described Rockefeller, who is cooperating with authorities, as a good human being, a strong person and someone who goes out of his way for others.
"I think it takes a strong man to come down and ... be honest -- and that's what Billy's doing. That's what strong men are. You know, strong men are people who can come out and tell it like it is, and, you know, be accountable. And that's what Billy is," said Bottalico.
He also said Rockefeller apparently "was nodding off and caught himself too late" before the accident that killed four people and injured 67 others. The engineer has not been charged.
"I don't believe that, in my opinion, that anybody could ever ... make Billy feel worse than he's making himself feel today. So Billy feels terrible. Whether it was his fault or not his fault, it's his train," said Bottalico.
Also speaking on the engineer's behalf Tuesday was Rockefeller's lawyer, Jeffrey Chartier.
The attorney has met with his client, police and National Transportation Safety Board representatives.
He said that Rockefeller worked as a volunteer firefighter and is married, with a stepson and a granddaughter.
"Billy's a good man and, you know, I hope he can move forward from here," said Bottalico.
CNN's Dana Ford and Ross Levitt contributed to this report.