CARB Fact Sheet: Locomotives
- Locomotives are self-propelled off-road equipment used to push or pull rail-mounted cars carrying freight or passengers.
- Diesel-powered locomotives emit multiple air pollutants, including diesel particulate matter, fine particulate matter (PM2.5), oxides of nitrogen (NOx) and greenhouse gases (GHG).
- Locomotives travel throughout the state to seaports, railyards and other locations that are near where people work and live.
- Exposure to toxic and harmful diesel emissions is known to lead to cancer and increases in asthma, cardiopulmonary illness, hospitalizations, and premature mortality.
- Communities near rail operations bear a disproportionate health burden due to their proximity to harmful emissions.
To help meet California’s public health, air quality and climate goals, staff are proposing an In-Use Locomotive Regulation. The Proposed Regulation would achieve emission reductions from diesel-powered locomotives and increase the use of zero-emission (ZE) technology.
There are several types of locomotive operators in California. Select a locomotive type to view the fact sheet.
Locomotive Emissions
- As of 2022, locomotives are projected to produce:
- Over 640 tons per year of PM2.5
- Over 29,800 tons per year of NOx
- Locomotive emission standards, called Tiers, are described in the graphs below. The standards are divided between two locomotive power levels, referred to as line haul (locomotives greater than 2,300 horsepower) and switch (locomotives 1,006 - 2,300 horsepower)
Line Haul Locomotive Emission Standards
Historic locomotives are not included in this PM2.5 graphic due to insufficient population data.
Switch Locomotive Emission Standards
Historic locomotives are not included in this PM2.5 graphic due to insufficient population data.
2020 California Locomotive Population by Tier
Historic locomotives are not included in this population graphic due to insufficient population data.
The Proposed In-Use Locomotive Regulation
1. Starting in 2024: Spending Account
- Locomotive operators would be required to fund their own trust account based on the emissions created by their locomotive operations in California. The dirtier the locomotive, the more funds must be set aside.
- Spending Account funds would be used to purchase the cleanest locomotives or upgrade existing locomotives to the cleanest tier.
2. Starting in 2030: In-Use Operational Requirements
- Only locomotives less than 23 years old would be able to be used in California.
- Beginning in 2030, all switch, industrial, and passenger locomotives with an original engine build date of 2030 or newer would be required to operate in a ZE configuration—i.e., qualify as either a ZE locomotive or ZE capable locomotive to operate in California.
- Beginning in 2035, all Class I line haul locomotives with an original engine build date of 2035 and beyond would be required to operate in a ZE configuration—i.e., qualify as either a ZE locomotive or ZE capable locomotive to operate in California.
3. Starting in 2024: Idling Limit
- All locomotives with automatic shutoff devices would not be permitted to idle longer than 30 minutes, unless for an exempt reason. Exemptions align with those described by U.S. EPA., and would be granted for reasons like maintaining air brake pressure or keeping the driver cabin heated or air conditioned.
4. Starting in 2024: Registration and Reporting
- Locomotives operating in the state would be required to register with CARB.
- Locomotive activity, emission levels and idling data would be required to be reported annually.
5. Additional Options Under the Proposed Regulation
- Alternative Compliance Plan: The Proposed Regulation offers an Alternative Compliance Plan, which would allow locomotive operators to reduce emissions through other strategies, provided those strategies are not already required. Alternative Compliance Plans must achieve emission reductions equivalent to or greater than those under the Proposed Regulation.
- Temporary Locomotive Operating Waiver: The Proposed Regulation allows operation of locomotives prohibited from operation in California under the In-Use Operational Requirement under specific circumstances, such as for maintenance
- Small Business Hardship Extension: The Proposed regulation offers a process for small businesses to apply for a temporary extension of their obligations under the Spending Account and/or the In-Use Operational Requirement.
- Historic Railroad Low-Use Exemption: Historic locomotive operators that meet specific requirements may receive permission to be exempt from obligations under the Spending Account and/or the In-Use Operational Requirement.
Emission Reductions from the Proposed Regulation
Total Emission Reductions (2023-2050): The Proposed Regulation is expected to reduce statewide locomotive emissions by approximately:
- 7,455 tons of PM
- 389,630 tons of NOx
- 21.9 million metric tons of GHG, roughly equivalent to removing all heavy-duty diesel trucks from California’s roads for all of 2030.
The graphs below show percent reductions (in tons per day) of PM2.5 and NOx that would be achieved in each operating type by 2050.
Statewide PM2.5 Locomotive Emissions by Type
Historic locomotives are not included in this PM2.5 graphic due to insufficient population data.
Statewide NOx Locomotive Emissions by Type
Historic locomotives are not included in this NOx graphic due to insufficient population data.
Costs and Benefits from the Proposed Regulation
Costs: Staff estimate that the total net cost of the Proposed Regulation would be $13.8 billion, including costs for new equipment and labor, with the costs to households averaging an estimated $42/year.
Benefits: It is estimated that the Proposed Regulation would eliminate approximately 3,200 premature deaths, 1,100 hospital admissions and 1,500 emergency room visits. Health benefits are monetized to quantify savings from the Proposed Regulation. CARB staff estimate $32 billion in monetized health benefits.
Decrease in Cancer Risk from the Transition to Tier 4 Locomotives
Cancer Risk: Using a conservative approach, CARB staff modelled cancer risk assuming all locomotive use in California is at an average of Tier 4 emission levels. In the two railyards modelled, it is estimated cancer risk would decrease by over 90%.
Incentive Funding for New Technology
Based on development timelines for new technology, CARB staff estimate that ZE passenger and switch locomotives would be commercially available by 2030, and ZE line haul locomotives by 2035. CARB would release a Locomotive Technology Feasibility Assessment along with the regulatory package prior to the Board hearing.
CARB offers grant funding to upgrade or replace locomotives to Tier 4 or ZE. Visit CARB Incentives for Locomotives for more information.
Next Steps
The Proposed In-Use Locomotive Regulation is anticipated to be presented to the Board in November 2022. For more information on the development of this Proposed Regulation, including opportunities to provide input, visit Locomotives and Railyards: Meetings & Workshops.