Separate actions for the environmental cleanup brought by state and federal agencies are not resolved by this settlement and are still pending. The National Transportation Safety Board (NTSB) is still investigating the accident but is not expected to release its final report until June. The agency already concluded that an overheated wheel bearing likely caused the crash. The suit settlement comes amid a backdrop of a board fight that could determine Norfolk Southern's operating model in the future. Activist investor Ancora Holdings is seeking to replace Norfolk Southern CEO Alan Shaw and more than half the company's board of directors due to lagging margins compared to railroad competitors. In March, the hedge fund came up with its own three-year plan for Norfolk Southern, which includes the full implementation of precision scheduled railroading (PSR).