After two years of investigation, federal safety regulators say they’re stumped over why a woman would stop her vehicle on a well-marked train crossing north of New York City and, with a commuter train barreling down on her, drive into its path. The impact between the Metro-North Railroad car and sport-utility vehicle of Ellen Brody on Feb. 3, 2015, killed her and five people on the train, making it the most deadly accident in the commuter line’s history. After studying everything from possible distraction to whether the train’s whistle could be heard inside her vehicle, the National Transportation Safety Board concluded that she acted for “undetermined reasons.” The death toll was exacerbated by the way the system’s electrified third rail was built, investigators said. The design of the power supply turned steel bars into lethal spears. The conclusions left Alan Brody, the husband of the 49-year-old mother of three, dissatisfied. He said warning signs at the Valhalla, New York crossing could have been improved and visibility at the curved intersection was poor. “No one wants to address the fact they have a failing system,” Brody said. “If you wanted improvement, you didn’t see it today.” The independent federal safety board finalized its final report on the crash Tuesday, including both its determination of the cause and recommendations for changes. After the train ferrying commuters north from New York City struck the Mercedes-Benz SUV, massive lengths of an electrified third rail running parallel to the train were lifted upward by the crumpled vehicle and flung one after another into the rail cars. Eleven sections of the third rail measuring a total of 343 feet (105 meters) penetrated the train, reaching as far as the second car and crushing passengers, according to NTSB. Five people in the train died from the impacts, and nine others were injured. The collision also caused the train to catch fire. New York Victims Among those killed was Eric Vandercar, 53, a senior managing director in institutional sales and trading at Mesirow Financial in New York. Others who died included Joseph Nadol, a 42-year-old JPMorgan Chase & Co. executive, and Walter Liedtke, 69, the curator in European paintings for the Metropolitan Museum of Art. Ellen Brody had been caught in traffic and was on an unfamiliar road when the train approached and the gates at the crossing came down on her car, according to witnesses. She got out of her car, but then returned to the vehicle and tried to drive forward. If Brody had run or merely stayed put, there may have been a collision but it would have been less severe, investigators concluded. The train hit her vehicle from the right side as it rolled onto the tracks. Brody was well rested, hadn’t taken in drugs or alcohol and wasn’t distracted by a mobile phone or electronic device, the investigation concluded. They also test drove a similar vehicle to see whether she could have accidentally driven forward when she meant to back up, but that didn’t seem likely, they found. One of the few hints about what may have led to her actions was her decision to get out of the car to examine the crossing gate after it hit her car, the safety board found. That gave her less time to react as the train approached. The driver behind her told investigators he had backed up when the gates came down to make room for her and motioned for her to back up, as well.  Unique Design of Third Rail May Hold Clues to Crash Severity Even though the train engineer was traveling below the speed limit and hit the emergency brakes, the impact carried the car 665 feet. The third rail sits just to the side of the main rails and carries power to the electric locomotives on Metro-North’s network. Unlike almost every other railroad using a third rail, it connects to the train with a device that runs along the bottom of the rail. While investigators didn’t find that the unique design was at fault, the tapered bar that first entered her car was sharp. When the train drove Brody’s car into the third rail, the pointy end of the first steel bar entered her car and was guided upward into the first rail car, according to previously released NTSB records. The accident investigators now believe that the third rail design should be studied to determine whether there are safer ways to construct it so that it would break apart rather than holding together as the train pushed into hundreds of feet of the steel bars. The NTSB issued recommendations to the U.S. Federal Railroad Administration and local railroads, including Metro-North, to conduct safety reviews and to make changes to third-rail design if warranted. In opening remarks for the meeting, NTSB’s acting Chairman Robert Sumwalt said the decision to drive into the well-marked train crossing was a lesson drivers should heed. “It doesn’t matter how clear the tracks look,” he said. “The next train is always coming. It’s just a matter of when.”