New York (CNN) -- Metro-North Railroad, the second largest commuter rail line in the country, has a "deficient safety culture" and overemphasizes on-time performance, according to a report released Friday by the Federal Railroad Administration.
The review, which comes after a 60-day safety assessment by the U.S. Department of Transportation's rail agency, said the focus on punctuality "has had a detrimental effect on safety, adversely affecting the inspection and maintenance of track and negatively impacting train operations."
Metro-North employees have reported feeling pressure to rush when responding to technical issues or needing more time to make necessary track repairs, according to the report.
"Currently, no single department or office, including the Safety Department, proactively advocates for safety" at the railroad, and there is no effort to identify or take accountability for safety concerns, the reviews said.
Joseph Giulietti, who took over for former Metro-North president Howard Permut in January, responded to the report at Grand Central Terminal on Friday.
"Safety was not the top priority. It must be, and it will be," Giulietti said.
"I have a clear message for our customers and our employees: Safety must come first at Metro-North. I will not allow any Metro-North trains to run unless I'm confident that they will run safely," he added.
In the report, the Federal Railroad Administration said Metro-North has a poor training and record-keeping system.
With 700 new employees hired in 2013, an effective training program for new and existing employees is critical for safe operations, according to the assessment.
"The emphasis on on-time performance, combined with the increased volume of train activity, appears to have led managers and supervisors to allow inspections, maintenance and employee training to lapse," the federal inquiry concluded.
Metro-North has 60 days to submit a plan to improve the training program and the effectiveness of its safety department, according to the review.
The three-month review was prompted by a derailment on December 1, 2013.
A Metro-North train of seven cars derailed while traveling from Poughkeepsie, New York, to Grand Central Terminal in New York City. The train was hurtling along at 82 mph, far over the speed limit of 30 mph for that section of track, as it approached a sharp bend in the Bronx.
The cars tumbled off the track, killing four passengers and leaving dozens more hospitalized. The lead car came to rest inches from water at the intersection of the Hudson and Harlem rivers.
"We at Metro-North are heartbroken at the loss of life that has occurred on this railroad," Giulietti said, adding that Metro-North plans to create a confidential close-call reporting system for employees to report safety issues.
Giulietti said that Metro-North officials also have plans to make personnel changes, to buy new equipment and install cameras inside the agency's trains.
"We have a lot of work ahead of us. But every problem I've seen here can be fixed -- and will be fixed," he said.
The December derailment was the fourth serious accident on the railroad since May 2013. In June, a Metro-North train was sent down a track closed for construction and fatally struck a foreman. In another incident, a Metro-North train derailed and was struck by a train on an adjacent track.
More needs to be done immediately to improve safety, said Federal Railroad Administration chief Joseph Szabo in a letter to the head of New York's transportation authority after the derailment.
"Safety is our top priority, and this in-depth assessment should serve as a wake-up call to Metro-North as they work to make their operations safer," said U.S. Transportation Secretary Anthony Foxx. "Efficiency and on-time performance are important, but they cannot come before the safety of every passenger on board or those communities along the system."