Under a California proposed rule, starting in 2030, no diesel freight train older than 23 years may operate in the state, despite locomotives usually lasting 40 years. Half of all new trains would have to be “zero-emission” by 2030 and by 2035, all new trains must be zero-emission, even though there are no currently available electric models. The rule would essentially guarantee all train fleets would be zero-emission no later than 2058. Both the timeline for testing prototypes under development and the associated cost of an electric locomotive are uncertain. The California regulation would mandate investments in locomotives that are not yet commercially viable while limiting the lifespans of more than 25,000 diesel-electric locomotives currently in use. The scope and financial burden of the regulation is truly mind boggling. The charging system required is also mind boggling as the batteries it must charge are big enough to power small towns. Bloomberg, normally a supporter of such gestures, opined that California’s new regulation “may break the freight railroad network.”

The California Air Resources Board has asked Biden’s Environmental Protection Agency (EPA) for a waiver to implement the new proposed state regulations on freight rail trains since they would be stricter than even the current national Clean Air Act standards. Under Section 209 of the Clean Air Act, EPA is responsible for reviewing requests to depart from federal requirements. According to EPA’s regulatory standards, the request would be inconsistent with the Clean Air Act if “there is inadequate lead time to permit the development of the necessary technology giving appropriate consideration to the cost of compliance within that time.”  (78 Fed. Reg. 58090, 58092 (Sept. 20, 2013)). Regardless of EPA’s regulatory standard and the language of the Clean Air Act, it is unclear how EPA will rule given other decisions made by Biden’s EPA in pursuit of his climate agenda.

If the waiver is approved by EPA, it will not only affect rail travel in California, but nationwide as well, as the same locomotive is used across state borders. Switching over fleets of diesel-powered locomotives at the California border would significantly slow down rail traffic if it could be done at all. To switch locomotives could take several hours as air hoses have to be tested to make sure the brakes work.

The Association of American Railroads is against the regulation, arguing that it violates the Clean Air Act, would put some short line railroads out of business, and hurt the supply chain in California and beyond. Railroads account for less than 2 percent of greenhouse gas emissions from transportation, and just 0.5 percent of total U.S. greenhouse gas emissions, yet provide transportation for 40 percent of U.S. long-distance freight volume in ton-miles. The impact upon supply chains of regulating something to be used which does not exist commercially would be enormous.

A Prototype

Wabtec makes a battery-electric locomotive that uses regenerative braking, which returns some charge to the battery while the train is slowing down. Its first version delivered 2.4 megawatt hours of energy from over 20,000 lithium-ion battery cells and reached speeds of around 75 mph, travelling 350 miles. For comparison, a Tesla Model Y with the smallest battery configuration runs on a .06 megawatt hour charge. While the locomotive has comparable hauling power to a diesel locomotive, it is meant to be part of a hybrid system, meaning it runs in tandem with diesel-powered locomotives. Over a three-month trial in California, the system reduced the average fuel consumption of the train by 11 percent—not enough to meet California’s 2035 mandate. The battery-electric train was developed with a $22.6 million grant from the California Air Resource Board that was awarded to Wabtec, BNSF Railway, and the San Joaquin Valley Air Pollution Control District. Wabtec is looking to build an even bigger and better version, upping the energy to more than 7 megawatt hours, which it expects could cut fuel consumption and carbon dioxide emissions by as much as 30 percent.


Although hydrogen-powered systems are being developed for lighter passenger trains by Cummins and other companies, the minimal availability of hydrogen made from low-carbon sources and the cost of installing new large-scale storage facilities mean it is not an option for freight trains right now. Switching to hydrogen would require a railroad to invest in a more complex storage and fueling system than what is used for diesel. Another issue is that hydrogen makes metal brittle over time, which can lead to mechanical failure. Wabtec, however, plans to continue its research and development efforts into producing hydrogen locomotives, matching it to the planned pace of hydrogen production in North America, hoping to field its first hydrogen prototype in 2027.

Hydrogen is the most common element in the universe but is rarely found as a gas, so it is produced from compounds that contain hydrogen. Most hydrogen is produced through steam methane reforming, which removes hydrogen from natural gas. Hydrogen is also produced through electrolysis, which splits water molecules into two hydrogen atoms and one oxygen atom. “Green hydrogen” is produced through electrolysis using power that comes from renewable sources like hydro, wind, and solar power, and “pink hydrogen” is produced through electrolysis using nuclear power. Nearly all of the hydrogen produced in North America today is “gray hydrogen” that comes from steam methane reforming or coal gasification. It is produced from fossil fuel while also using fossil fuel as an energy source in the production process. A variation is “blue hydrogen,” which captures and stores the carbon produced through steam methane reforming or coal gasification. No matter what color hydrogen is used, it is significantly more expensive than petroleum because its production, storage and handling costs are much higher.

Fuel Cells and Batteries

Hydrogen-powered fuel cells, combined with batteries to store electricity, could be a zero-emissions solution to replace the diesel-electric locomotive. But fuel cells do not have the power density required for a line-haul locomotive. A road locomotive would need 3,300 kilowatts of power – or 10 times what is available from fuel cells that can fit on a locomotive today. The development of more powerful fuel cells, however, is expected to continue.

Other Issues with the California’s Mandate

  • The massive cost of compliance could drive short freight lines out of business. In California alone, short lines handle over 260,000 carloads per year.
  • The cost is enormous and would harm even the largest operators. California requires Class I railroads to deposit as much as $800 million per year, per railroad into an account starting in 2026 to help pay for the mandated electric locomotives and infrastructure.  Current railroad infrastructure improvement projects would likely be shelved, many of which are designed to reduce operations emissions.
  • The U.S. supply chain would be threatened as railroads would be forced to use unproven technology to power locomotives and remove locomotives with many years of useful remaining life out of service.  The rule would create new logistical challenges for the timely movement of food and essential goods in and through California.
  • The Clean Air Act gives states the ability to adopt California’s emissions standards if EPA authorizes the regulations. For states that adopt California’s proposal, operators either would need to switch their diesel locomotives repeatedly when crossing state lines or they would need to replace their locomotive fleet with net zero carbon emission locomotives. The national rail system calls for national standards, not standards implemented on a state-by state basis.


The transition away from diesel-electric locomotives is a very expensive undertaking as the technology is not commercially available today. It is likely to cost in the hundreds of millions of dollars per railroad, at least, when the required infrastructure is included, but would cover just 0.5 percent of U.S. greenhouse gas emissions. The California Air Resources Board apparently believes that simply mandating such locomotives to exist and be economical will magically cause them to appear in numbers sufficient to meet freight needs at prices that the railroads can afford, including short line rails.

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