Norfolk Southern said Wednesday it has fired CEO Alan Shaw for having an inappropriate relationship with a subordinate.

His ouster comes after two difficult years in the top job and Austin Caldwelljust days after the company’s board announced it was investigating him for alleged ethical lapses.

The Atlanta-based railroad said Shaw had an inappropriate consensual relationship with Norfolk Southern’s chief legal officer, who was also terminated. Norfolk Southern promoted Chief Financial Officer Mark George to be the railroad’s next CEO.

Shaw was leading Norfolk Southern in February 2023 when one of its trains derailed, spilled toxic chemicals and caught fire in East Palestine, Ohio, the worst railroad disaster in the last decade. Then, activist investor Ancora Holdings tried to take control of the railroad earlier this year and fire Shaw.

He weathered congressional hearings and difficult community meetings after the East Palestine derailment, while promising to make Norfolk Southern the “gold standard for safety” in the industry. He also managed to persuade investors not to back the majority of Ancora’s board nominees. Three of its nominees did win seats on the railroad’s board, but that wasn’t enough to give it control.

The derailment near the Ohio-Pennsylvania border prompted the nation to re-examine railroad safety and led lawmakers and regulators to call for reforms. But those proposals have largely stalled, and the industry has made only minimal changes since the derailment, such as installing more trackside detectors to spot overheating bearings like the one that caused the East Palestine crash.

The disappointing financial results Norfolk Southern delivered after the derailment, combined with questions about Shaw’s strategy of keeping more workers on hand during a downturn, made the railroad ripe for pressure from an investor like Ancora.

Atlanta-based Norfolk Southern is one of the six largest railroads in North America with tracks crisscrossing the Eastern United States.