It was the first crash in the 30-year Metro-North history to result in passenger death and the deadliest in the city since a 1991 subway derailment at Union Square. An NTSB investigation determined that the train operator was at fault and had entered the curve much too quickly, entering a 30mph curve at 82mph, causing the train cars to tip over and derail. A CSX train had derailed near the same location just five months earlier and the accidents brought renewed attention to the use of Positive Train Control, which upgrades the technology overseeing train traffic. The MTA had agreed in 2013 to install Positive Train Control on the LIRR and Metro-North, but an investigation after the Metro-North derailment found the project had made almost no progress. A report by the Federal Railroad Board found Metro-North overemphasized on-time performance while also failing to provide sufficient safety training.