The National Transportation Safety Board (NTSB) has yet to confirm a conclusion as to why the train derailed. Still, evidence suggests it started with an overheated wheel bearing in the 23rd car. The train's crew was alerted to the danger via a safety monitoring system, but by the time they were able to slow down and finally stop the train, 38 cars had derailed. Eleven of those cars carried toxic chemicals. When the crew stepped off the train to assess the damage, they saw fire and smoke and quickly alerted authorities.The train had 149 cars in total and was 9,000 feet long. Devices are installed along the railroad lines to detect and report issues as trains pass along the tracks. One device recorded increasing temperatures about 30 miles east of East Palestine. The detector that triggered the alarm was located 19 miles east of the city, recording temperatures of 253 degrees Fahrenheit. While the engineer reacted immediately to the alarm, the wheel bearing failed before the train could come to a halt. Still, there is no evidence that the crew did anything incorrectly. As with many disasters of this proportion, federal regulators are looking at making changes to lessen the likelihood of a similar accident in the future.