California Emissions Regulation for Intrastate Locomotives Pathway: Energy Efficiency, Conservation, and Fuel Switching in Transportation → Heavy-Duty Vehicles and Freight → Setting Emissions Standards for LocomotivesJurisdiction: States and State Governments While California cannot regulate interstate locomotives, it has promulgated an emission standard regulation of wholly intrastate locomotives at Cal. Code Regs. Tit. 13, 2299.