The NTSB released a huge tranche of documents in the public docket for the case in February, but offered little in the way of conclusions about the cause of the accident.
The theory that Bostian might have been affected by rocks hitting the train emerged early on. There’s a logic to it: Trains are often struck by rocks, especially in the urbanized corridors of the Northeast. Besides, another train—a regional Philadelphia SEPTA train—had been “rocked” the same evening, and Amtrak 188 passed that train where it had pulled off, in part because the engineer had been injured by glass after being struck. NTSB concluded that though the windshield of Amtrak 188’s locomotive was cracked, the train had not been rocked.
Instead, Bostian was distracted by the radio traffic concerning the SEPTA train, which apparently prevented him from throttling down at a crucial moment. The area where Amtrak 188 derailed features several stretches where a train speeds up and slows down, but instead of slowing down when it should have, the train sped up to 106 miles per hour just before derailing. Investigators speculated that though Bostian knew the route well, his distraction might have led him to believe he had already passed the curve, so that he sped up too soon.
Bostian remains an enigma—the tragic figure at the center of the disaster. He cooperated with investigators, and reported having no memory of the time leading up to the crash, though the NTSB reported that the engineer had been moving the throttle during that stretch. He was concussed in the accident. Obsessed with trains since his childhood, Bostian had worked to achieve his dream job as engineer. Colleagues interviewed after the crash recalled him as an excellent engineer, toxicology tests came back negative, and his phone was turned off at the time of the derailment. The train was on time, and there was no indication that Bostian was trying to make up for lateness, a factor in some legendary train wrecks.
While the NTSB ruled out mechanical failure as a cause for the crash, it also found that windows on the train popped out, and that if the windows had remained in place, some passengers would not have been ejected, and might not have been as badly injured.
The fact that an engineer like Bostian could be at the controls for a horrific accident is chilling, but as Hart noted, it’s not the only case. There were deadly rail crashes in California in September 2008 and the Bronx in December 2013, both of which would likely have been avoided by PTC. In total, NTSB has calculated that PTC would have prevented 145 accidents since 1969, in which 288 people were killed and nearly 6,600 were injured.
Amtrak has since implemented PTC on the stretch in Philadelphia where the crash occurred, as well as throughout most of the Northeast Corridor. Generally, however, the United States has been slow to adopt the technology. In 2008, Congress mandated that every railroad with intercity passenger service, commuter service, or hazardous materials install PTC by the end of 2015. But railroads have pushed back on the mandate. Amtrak, which is perpetually strapped for cash, said it could not afford to meet the deadline. Commercial railroads have lobbied aggressively against the deadline as well, and late last year Congress agreed to extend the timetable by at least three years, to the end of 2018.