National Transportation Safety Board member Earl Weener said Monday that the Metro-North Railroad train was going 82 mph as it entered a 30 mph turn and derailed Sunday. Four people were killed and more than 60 others were injured.
Investigators haven't determined whether the cause was human error or mechanical trouble. Still, some safety experts say the tragedy might not have happened if Metro-North had what's called positive train control technology.
Metro-North is working on it. But, like many rail lines, Metro-North has advocated for extending a 2015 deadline to implement the costly and complicated system.