The National Transportation Safety Board says that preliminary data shows that the Metro-North train that derailed in the Bronx was traveling 82 miles per hour before derailing while traveling around a curve that was in a 30-mile-per-hour zone.
NTSB board member Earl Weener said that the throttle of the train was reduced to idle approximately six seconds before the rear engine of the train came to a stop.
Weener said that the brakes were fully applied five seconds before the train came to a stop.
The zone leading up to that 30-mile-per-hour curve was a 70-mile-per-hour zone, according to Weener.
According to Weener, it is still unclear whether human error or faulty equipment resulted in the train's derailment.
He said that officials need to understand how the brake system was working during the earlier part of the trip, when the train made nine stops.
Investigators say there was surveillance footage of the crash, but they said that it has to be sent to the lab to be enhanced because of poor quality.
According to Weener, the NTSB began interviewing the engineer and the train's three other crew members Monday.
Weener said that no problems with the brakes were reported during the train's trip.
All seven cars of a southbound train on Metro-North's Hudson line derailed just north of the Spuyten Duyvil station in the Bronx early Sunday morning.
Four people were killed, and more than 60 were injured.
All seven train cars involved in the derailment were removed from the scene Monday.
Two of the cars were taken to a nearby Metro-North facility so that they can continue their investigation.
The NTSB has released the track back to Metro-North for them to begin repairs.
Meanwhile, the MTA says that service on the Hudson Line will still be limited Tuesday.
There will still be no service south of Yonkers.
If you're headed to Westchester, you'll want to take the number 1 train from Times Square to 242nd Street-Van Cortlandt Park, where you can catch a shuttle bus to Yonkers.
You can also take Metro-North's Harlem or New Haven lines as an alternative.
For more information, go to mta.info.