How US freight rail became dirtier than coal-fired power plants

BNSF Railways, a crown jewel of Warren Buffett’s Berkshire Hathaway, claims to be an environmental leader within the U.S. railway industry, with the cleanest fleet of locomotives in North America.

In its latest sustainability report, BNSF urges people to "think green" when they see the steel wheels of orange locomotives and freight cars moving along steel rails.

The company has the biggest share in an industry with a serious pollution problem. According to government data, U.S. railroads emit more nitrogen oxides, the main component of smog than all of the coal-fired plants combined.

U.S. railways produced together about 485,000 tonnes of nitrogen oxides in 2024, compared with 452,000 tonnes emitted by U.S. power plants that burn coal, according to a calculation based on reported annual fuel consumption multiplied the EPA’s 2023 average weighted emission rates.

BNSF is the largest freight railroad in the United States. It accounts for a third of that total and will produce 161,500 tonnes of smog causing nitrogen oxide by 2024. "We don't dispute your number. BNSF stated in an email that it is the largest Class I railroad based on volume. Morningstar railroad analyst Greggory Warren believes that BNSF’s position as the largest rail company in the United States, and its profitability will be challenged if a $85 billion merger of Union Pacific with Norfolk Southern is approved by regulators. This would create the U.S.’s first coast-to-coast rail freight operator.

Four industry experts agreed that the calculations were fair. Class I railroads produce 80% of all NOx tonnes produced in the industry. Class I refers to six major railroads that generate more than $1 billion annually.

BNSF has not reported on its share of the recent NOx emission performance of the rail industry, or the factors that are driving the high levels of pollution.

According to the EPA’s Co-Benefits Risk Assessment Tool, railroad locomotive pollution costs the United States $48 billion annually in healthcare costs. It also causes 3,100 premature deaths.

Bill Magavern is the policy director for Coalition for Clean Air in California, an organization that promotes public health. He said that the EPA should force railroads to upgrade their fleets.

The EPA declined comment on rail pollution specifically for this article, but stated: "The Trump EPA has a commitment to enhancing its ability to provide clean air, land, and water for all Americans."

AGGING FREIGHT LOCOS

Railroads' poor performance in terms of emissions is mainly due to the fact they have stopped replacing their aging locomotive fleet. According to EPA reports and industry reports, the average age of U.S. trains is 28 years old, compared to 20 years in 2009.

This is a problem, because the federal emission?standards are based on the age of the locomotives. The oldest locomotives have the lowest limits.

The U.S. rail freight industry has been slow to buy new locomotives because there is no requirement for retiring old ones. This fear of new regulations that could be implemented by future administrations may have exacerbated the situation.

Edward Markey, a Massachusetts Democrat Senator, claims that railroads are no longer interested in innovation. Markey stated that the air pollution standards of railroads have a loophole the size of an engine, which is being used by companies to keep dirty, old trains on tracks.

Rail industry claims that rail is the most environmentally friendly option to transport freight on land. They cite data from the U.S. Department of Transportation. A locomotive can transport a ton (about 500 miles) of freight on one gallon of gasoline, which is up to three or four times as efficient as trucks.

The Association of American Railroads also said that it was unfair to compare rail with?powerplants, saying locomotives had little choice but diesel. The power plants in question have many other options to generate electricity - hydropower, wind, coal, natural gases, etc. The rail industry is different, the trade group said.

BNSF has said that it will reduce its emissions by improving efficiency and technology. It also stands behind its claim of having the cleanest fleet based on its number of modern locomotives.

BNSF reported that 360 of the 6,780 locomotives it owns are modern locomotives, Tier 4 engines, which meet the strictest federal emission standards. This is the largest number in the entire industry.

Surface Transportation Board data shows that only 5% of the total fleet is in use or stored. Analysts and CN press release about new locomotives claim that Canadian National's rival has about 300 Tier 4 engines, which make up 27% of their total fleet. BNSF's closest competitors operate about 270 Tier 4 locomotives at Union Pacific, and about 225 at CSX Corp. EPA data and company press releases, as well as trade industry reports, show that there are about 80 Tier 4 locomotives at Norfolk Southern and 270 at Union Pacific.

BNSF spent 394 million dollars on?165 rebuilt and new locomotives between 2020 and 2024. This was a 69% decrease from the previous five years, when the company spent $1.26billion on 558 engines. According to BNSF's annual reports filed to the U.S., the replacement of aging locomotives--some lasting as long as 40 years-slowed down sharply. Surface Transportation Board.

CLEANEST FEET?

BNSF's large size is not the only reason for its high emissions.

According to statistics submitted by the U.S. Department of Transportation, BNSF has the lowest fuel efficiency amongst the six largest railroads in the United States. Surface Transportation Board is the industry's economic regulator.

BNSF used 1.14 gallons per ton of weight moved over 1,000 miles in 2024. This industry metric is called a gross-ton mile. Union Pacific used 1.08 gallons of diesel to move the same amount of weight over the same distance. The most efficient railroad, Canadian National, consumed 0.88 gallons.

According to railroad industry analysts interviewed, BNSF's fuel efficiency is low because it transports more intermodal cargo than its peers.

The high-priority containers must move faster than normal freight, as they are usually more time-sensitive. This is according to Jason Kuehn a vice president and railroad analyst at the consulting firm Oliver Wyman.

BNSF will ship 5.3 million intermodal shipments in 2024. This is nearly 60% more than the No. According to the company's disclosures, Union Pacific is ranked No. 2.

Analysts say BNSF is likely to be less efficient due to its limited use of precision-scheduled railing. This industry practice aims at reducing fuel consumption and costs by using longer trains, fewer engines, and a shorter idle time. Fuel efficiency is also affected by mountainous terrain, and the congestion of a railroad network.

BNSF refused to comment on why it has a relatively low fuel efficiency, but maintained that it was an environmental leader 'in the industry based upon its adoption of the new locomotives which allows it to burn fuel cleaner.

The company said that it had the "cleanest fleet" of locomotives and platform locomotives.

It refused to give details about its fleet-wide emission intensity and could not verify whether it was better than competitors.

According to the EPA, Tier 4 locomotives reduce NOx by up to 80% compared with Tier 3 models.

Fear of Regulation

Railroads have stopped investing in new locomotives because of new regulations, including zero-emissions standard proposed by California. They are concerned that these new rules could make them obsolete.

Roger Nober, former chief legal officer of BNSF and director of George Washington University’s Regulatory Studies Center, said: "These locomotives are 40-45 years old, but you say they won't be able use them because we will have zero emissions."

"Railroads do not see this as an efficient use for their capital."

In 2008, EPA hoped that it could clean up the freight rail industry by setting higher standards for new locomotives. These standards included new Tier 3 models and Tier 4 models. Rail companies have slowed their purchase of new locomotives in order to encourage the replacement of older locomotives.

The EPA predicted in 2008 that by 2025, at least 30 percent of freight locomotives will be operating within the most stringent limits. According to the EPA, only 6.5% out of 19,303 locomotives that are currently active and operated by the six major railroads will meet this limit in 2023.

According to the U.S. Office of Transportation and Air Quality, American railroads had replaced their locomotives annually at a rate of 4% before 2008. By 2024 the replacement rate for the railroad industry had fallen to 0.5% annually.

Neither BNSF, nor its competitors provide precise data about the model year of?active locomotives within their national fleets.

The industry's biggest battle has been against California's proposed emission standard. This would have prohibited locomotives older than 22 years from operating within the state and required that all locomotives be zero-emissions in 2035.

California, with its large market size, can set a standard for the nation.

According to officials at the California Air Resources Board, the stricter regulations would reduce 7,400 tons diesel soot and 386,000 tons NOx by 2050. They also estimate that the cancer risk of those who live near rail operations could be reduced by 90%.

Rail officials claim that the bill would also have prohibited 65% of freight locomotives in operation from operating within the state.

California retracted the proposal a week before Donald Trump was inaugurated as U.S. President in January.

Trump is a frequent critic and would be expected to block this initiative by refusing California the waiver needed to establish state pollution regulations that are stricter than federal ones.

House Republicans introduced in May the Locomotives Act. This would prevent California from receiving such waivers. The bill was referred to Energy and Commerce Committee.

FIGHTING GREEN SCIENCE AND TECHNOLOGY

Rail industry lobbyists have also been very active in opposing the adoption of new technologies. BNSF informed the EPA at a public meeting last year that its test of a battery electric locomotive did not deliver enough power to transport tons of freight across long distances.

John Lovenburg said that the battery contained two megawatts usable energy. This is about 1/40th the energy needed for locomotives that haul line-haul freight.

Alex Scott, professor of supply-chain management at the University of Tennessee, says that electric locomotives can be used for short routes, replacing diesel locomotives, and in switch yards. However, for longer distances, they are limited by their battery weight.

In the United States, and in other parts of world, battery-electric locomotives do not exist. In China, India, and Russia the majority of freight locomotives are powered by overhead electric lines or catenary system.

According to an Association of American Railroads study from February 2025, electrifying 139,000 miles of track by six major railroads in North America could cost over $1.1 trillion.

Scott explained that the railroad industry was slow to adapt new technologies because, if there are problems, they're not only yours. You're creating issues for your customers as well as other railroads, because they all share the same track.

(source: Reuters)