NTSB investigation into subway derailment reveals wheel movement
According to preliminary results released Wednesday by the National Transportation Safety Board, the wheels of a Metro vehicle derailed, prompting a federal investigation and the suspension of more than half of Metro’s fleet. , moved 2 inches apart. Metro considers wheels that move more than one sixteenth of an inch to be unsafe.
https://www.washingtonpost.com/transportation/2021/12/01/metro-derailment-ntsb-investigation/ NTSB investigation into subway derailment reveals wheel movement