Association of American Railroads v. Randolph

On April 17, 2025, the federal district court for the Eastern District of California approved a request by the parties to a lawsuit challenging the California Air Resources Board’s (CARB’s) In-Use Locomotive Regulation to hold the case in abeyance. Prior to Inauguration Day, CARB withdrew its request to EPA for a Clean Air Act preemption waiver for the Regulation. The parties to the case challenging the Regulation subsequently agreed that CARB would propose to repeal the Regulation in full and that the railroad industry groups challenging the rule would voluntarily dismiss their complaint if the repeal was approved by May 30, 2026. The industry groups, environmental groups that intervened to defend the rule, and CARB also agreed “to hold a series of working groups to discuss potential ways to reduce emissions from rail activities, on a voluntary basis, in the State of California.”

The federal district court for the Eastern District of California stayed an action challenging California’s In-Use Locomotive Regulation, which sets emissions standards for locomotives operating in California. The court concluded that the primary jurisdiction doctrine required the court to stay consideration of claims that the regulation was preempted by the Interstate Commerce Commission Termination Act or violated the dormant Commerce Clause pending the U.S. Environmental Protection Agency’s review of the regulation to determine which portions require EPA authorization and whether to authorize those portions for which EPA authorization would be required. The court also ruled that the plaintiffs did not have standing to challenge certain aspects of the regulation that concerned idling requirements.