The California Air Resources Board (CARB) passed a first-in-the-nation rule on Thursday aimed at reducing the emissions diesel-fueled locomotive engines generate.

“Locomotives are a key part of California’s transportation network, and it’s time that they are part of the solution to tackle pollution and clean our air,” CARB Chair Liane Randolph said in a statement.

The new In-Use Locomotive Regulation would ban the operation of locomotives that are more than 23 years old by 2030, while prohibiting those with auto-shutdown features from idling for more than 30 minutes next year. 

The rule would also require operators to deposit funds into a spending account starting in 2024, based on the emissions they generate while in California. Companies would then be able to use those funds to upgrade their technology to cleaner alternatives.

Switch, industrial and passenger locomotives built in or after 2030 would be required to operate in zero-emissions configurations while they are in California, while freight line haul would have to do so by 2035.

“With the new regulation, we are moving toward a future where all transportation operations in the state will be zero emissions,” Randolph said.  

In order for California to advance this unprecedented regulation, the state will need to obtain approval from the Environmental Protection Ministry (EPA) because the rule would be more stringent than federal standards.

The Golden State must apply to the EPA for a special waiver because the Clean Air Act includes a provision prohibiting states from implementing their own emissions standards. California has been receiving approvals on individual rules for decades — a precedent that began in 1967, with the goal of combatting historic Los Angeles smog.

If California receives the EPA’s authorization on the locomotive regulation, other states would be able to follow suit.

Similarly, when CARB voted to ban the sale of gas-powered cars by 2035 in August, other states quickly expressed their intentions to follow.

Locomotives, which are fueled by diesel, emit multiple pollutants into the environment, including diesel particulate matter, greenhouse gases, nitrogen oxides and fine particulate matter, according to CARB.

At the same time, these self-propelled vehicles push and pull rail-mounted cars through areas where people live and work, such as seaports and rail yards, the agency stressed.

CARB estimated the resultant reduction in nitrogen oxide and diesel particulate matter — of which there is no known safe level of exposure — will create $32 billion in health savings by preventing about 3,200 premature deaths and 1,500 hospital visits.

Environmental activists applauded the board’s decision on Thursday, with Earthjustice attorney Yasmine Agelidis describing the rule as “a nation-lead standard.”

“The locomotive rule has the power to change the course of history for Californians who have suffered from train pollution for far too long,” Agelidis said in a statement.

“It is my hope that our federal regulators follow California’s lead and bring much-needed relief to environmental justice communities living near rail yards across the nation,” she added.