Norfolk Southern, the beleaguered freight railroad giant, said on Wednesday that it had fired its chief executive, Alan H. Shaw, for having an affair with the company’s chief legal officer.

In a news release, Norfolk Southern said Mr. Shaw, who became chief executive in May 2022, had a consensual relationship with its top lawyer, Nabanita C. Nag, who was also fired.

Mark R. George, the company’s chief financial officer, was named president and chief executive officer, Norfolk Southern said.

“This change in leadership comes in connection with preliminary findings from an ongoing investigation that determined Shaw violated company policies” by engaging in a relationship with Ms. Nag, the company said. “Shaw’s departure is unrelated to the company’s performance, financial reporting and results of operations.”

Mr. Shaw’s departure ends a troubled tenure at the top of Norfolk Southern. After one of its trains derailed in an Ohio town last year, spilling hazardous materials, Norfolk Southern faced lawsuits, government investigations and scrutiny from Congress. This year, an activist investment firm tried to take control of Norfolk Southern, and though it failed to dethrone Mr. Shaw, shareholders voted to place three of the firm’s directors on the company’s board.

Mr. Shaw is the latest of a number of corporate executives who have lost their jobs over violations of company policies.