Federal regulators on Thursday launched a 60-day safety assessment of Metro-North Railroad following the Dec. 1 derailment that killed four people and left 70 others injured, officials said.
Teams will review the commuter railroad's compliance with federal regulations, its procedures and practices and its safety culture, according to a statement by the U.S. Department of Transportation.
Federal investigators have said the early morning train from Poughkeepsie was traveling nearly three times the 30-mile-per-hour speed limit when it left the tracks near the end of its run to New York's Grand Central Terminal.
The train engineer has told authorities he became dazed and lost focus before the crash.
"Safety is our top priority, and this in-depth investigation will help ensure that Metro-North is doing everything possible to improve its safety record," said U.S. Transportation Secretary Anthony Foxx in the statement.
Transportation experts will look at track and signal maintenance and repair, communications, control center procedures, fatigue management and medical requirements for operating crew, among other safety checks.
The DOT's Federal Railroad Administration will issue its findings and recommendations once the assessment is complete.
Federal regulators issued an emergency order last week requiring Metro-North to implement urgent temporary safety measures to make sure its crews did not exceed speed limits.
They also ordered the railroad to come up with modifications to its control systems in order to improve mechanisms providing advance warning to engineers about excessive train speed.
The train that derailed was equipped with an alert system which was supposed to set off an audible alarm if the engineer did not touch the controls every 25 seconds. However, the alarm system was in the unmanned diesel locomotive pushing the train from the rear and not installed in the control cab where the engineer was driving the train.