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California passes rule to drastically cut locomotives’ emissions

California Air Resources Board regulation requires ‘cleaner locomotive technologies’

The California Air Resources Board has passed a rule regulating locomotives' emissions. (Photo: Jim Allen/FreightWaves)

Operators of passenger and freight locomotives in California will eventually need to move away from diesel locomotives and toward “zero-emission configurations,” according to a regulation that the California Air Resources Board approved Thursday.

CARB defines “zero-emission configurations” as a zero-emission locomotive or a zero-emission-capable locomotive, according to a fact sheet on the regulation. 

The new rules, which CARB says are aimed at reducing the emissions of locomotives operating within California, have two notable deadlines: Switch, industrial and passenger locomotives built in 2030 or after will need to operate in zero-emissions configurations, while locomotives built in 2035 for freight linehaul operations will need to comply with the zero-emissions configurations.

The new rules also limit locomotive idling to 30 minutes except for certain circumstances, such as maintaining air brake pressure or providing heat or cooling to the locomotive cab, and they require locomotives operating in the state to register with CARB and annually report on their activity, emission levels and idling data. These two conditions would go into effect in 2024.


To help companies with the transition, they can set up and deposit monies into a spending account that will go toward purchasing or upgrading to cleaner locomotive technologies, CARB said. 

There is also some flexibility for companies needing to comply with the rules if technologies aren’t available or an emergency situation arises, CARB said. 

“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 news release. 

The agency said emissions reductions from the new rules are estimated to equal or double the emissions from all passenger vehicles in California between now and 2050.


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

In preparing the regulation, CARB had determined that locomotive emissions would be greater than emissions from trucks. This would be due to the shift toward zero-emissions trucks in California, per CARB regulations. CARB is seeking to accelerate a target requiring zero-emission vehicles in California’s trucking sector to 2036 from 2040. 

CARB’s regulation on locomotive emissions would affect Class I railroads Union Pacific (NYSE: UNP) and BNSF (NYSE: BRK.B). Both railroads have been involved in testing alternatively powered locomotives with state officials.

In response to CARB’s decision, UP told FreightWaves: “Union Pacific is deeply disappointed in the California Air Resources Board’s decision to impose burdensome regulations on the railroad industry, which fail to take into consideration that the technology and infrastructure needed for success do not exist.”

Still, UP said it is “committed to achieving net zero carbon emissions by 2050 and [we] are making significant strides in addressing criteria pollutants. For example, we are investing $1 billion to modernize locomotives, signed a $100 million deal to test battery-electric locomotives, and are testing biofuel blends to improve carbon and criteria pollutant emissions. We are dedicated to ongoing collaboration to find balanced solutions.”

Rail industry’s response to new rule

The freight rail industry sees unresolved issues that would make compliance with the new rules challenging: Neither the technology nor the infrastructure is ready for this rule.

“Railroads, suppliers and government agencies all share the same goal of reducing emissions, and the industry has invested billions to that end,” the Association of American Railroads told FreightWaves. “Today, there is no clear path to zero-emissions locomotives. Mandating that result ignores the complexity and interconnected nature of railroad operations and the reality of where zero-emission locomotive technology and the supporting infrastructure stand.”

AAR also noted that freight railroads already can move a ton of freight nearly 500 miles on a single gallon of fuel. The group’s fact sheet, citing data from the U.S. Environmental Protection Agency, says that freight railroads account for just 0.5% of total U.S. greenhouse gas emissions and 1.7% of transportation-related greenhouse gas emissions. 


“For rail, California has long been the proving ground where the industry and government partners worked collaboratively to drive significant gains. Today, the industry continues to pilot technologies that could drive even greater progress in the state. The railroads’ commitment to helping the state reduce emissions and making operations more sustainable nationwide has not wavered,” AAR said.

“What has changed is CARB, which has turned its back on that proven partnership with the industry, appreciation of the state of technology and commitment to real progress over politics. Ultimately, CARB’s decision is entirely untenable and will not result in emissions reductions. Moreover, CARB lacks the legal authority to promulgate the In-Use Locomotive regulation, as it has conceded in the past.”

Meanwhile, the American Short Line and Regional Railroad Association previously expressed concerns that the costs to implement the new rules would be cost prohibitive for some short line railroads, with estimates of between $5 million and $7 million for each new compliant locomotive. 

Another concern is the legality of CARB’s rule since locomotives — including the ones that travel to California from out of state — participate in interstate commerce. 

“Combined with necessary infrastructure upgrades needed for things like hydrogen fueling or battery recharging, other regulations from local air districts in some parts of the state mandating additional improvements such as exhaust scrubbers in shop facilities, and new indirect emission source rules, these new regulations would significantly destabilize the state’s short line railroad industry, which already operates on relatively small profit margins,” ASLRRA said in an April 2021 statement to CARB. “The result of such a destabilization would be California shippers cut off from rail service, impacting their cost structure and ability to compete effectively in the U.S. and world economies.”

CARB said Thursday that the rule will reduce local communities’ exposure to air toxins, particularly for those communities that live within one mile of locomotive operations. 

Environmental advocate Earthjustice said the regulation would clean up the air in communities situated nearby rail yards.

“There are few places where this dirty diesel locomotive pollution is more saturated than in communities located near railyards. Southern California’s Inland Empire and Los Angeles regions are all too familiar with locomotive pollution,” Earthjustice senior associate attorney Yasmine Adelidis said Wednesday on the group’s website. “Not only do these areas suffer from some of the worst air quality in the country, but of the 18 major railyards in California, at least 10 are situated in this region.”

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7 Comments

  1. Brian Livingston

    Perhaps a CARB surcharge – listed separately on each invoice for California – would help everybody what is driving costs. Just a thought…

  2. Douglas Edwards

    I quit hauling freight to and from California years ago , and I think the railroad should quit doing business in California also.

  3. Ted

    The transportation industry as a whole has the power to pur California in check. “Just say no”!!! We won’t bow down to your onerous nonsense. Nothing in nothing out. To those who say it can’t be done because California is the 5th largest economy. It won’t be for long if you can’t ship anything. There are other ports besides SF & LB.

  4. Trucker Rob

    It’s about time California focuses on those dirty locomotives, that haul all that coal in there to produce electricity for those pretty BEV’s.

  5. C Reynolds

    California keeps pushing burdensome regulations without regard as how it will affect its population. There will come a time in the near future where NoOne will transport freight into or out of California. I’m already there. My fleet transpirts NOTHING to the west coast. You keep voting these Nazis into office and positions of power. You are the masters of your own demise.

Comments are closed.

Joanna Marsh

Joanna is a Washington, DC-based writer covering the freight railroad industry. She has worked for Argus Media as a contributing reporter for Argus Rail Business and as a market reporter for Argus Coal Daily.