Federal regulators have offered several recommendations to improve the safety of Metro-North employees and passengers.
National Transportation Safety Board members say there needs to be better training for doctors to identify and treat sleep disorders.
They say the Metropolitan Transportation Authority had developed a "culture'' that sacrifices safety for the sake of on-time performance.
During a meeting, they discussed a report on safety issues identified in five Metro-North accidents in 2013 and 2014 that killed a total of six people and injured 126.
Among the accidents was a deadly train derailment in the Bronx last December. It was caused when an engineer fell asleep at the controls.
Regulators say if certain measures were in place, the accidents could have been prevented.
"I can tell you there's no surprises," said MTA Chairman and CEO Thomas Prendergast. "There's been a spirit of cooperation from the time the first investigators set foot on the property, and there's been a sharing of information, not only between Metro-North and the NTSB, but we've shared that information across the agencies. And what they talked about in terms of culture, we accept, but there are actions well underway at all the agencies to address those, and they've been underway for months."
Regulators also say railroads should routinely screen employees for sleep disorders, but they note that screening for engineers in the New York City subway was in place before the Bronx derailment.