The Environmental Protection Agency (EPA) is finalizing revisions to its regulations addressing preemption of State and local regulation of locomotives and engines used in locomotives. This rule implements a policy change to no longer categorically preempt certain State regulations of non-new locomotives and engines, aligning with the plain text of the Clean Air Act (CAA), and better achieving the legislative intent of providing for exclusive Federal regulation of new locomotives and new locomotive engines while preserving the ability of California and other States to adopt and enforce certain State standards regulating non-new locomotives and engines.