Is the Rail Freight Industry a Sustainable Logistics Mode?

Although the rail freight industry is generally considered a sustainable part of the logistics sector, US freight railroads act as a major source of pollution.

Reuters has found that BNSF Railway sits as the largest contributor of high emissions, despite claims of being an environmental leader.

However, uncertainties to regulations and high expenses are creating barriers to sustainable logistics.

Freight pollution

Despite rail freight generally considered to be a sustainable branch of logistics, it has been found to be a major polluter. US freight railways contribute more nitrogen oxide emissions than all of the US's coal-fired power plants combined. Nitrogen oxide is the primary component of smog, contributing to a polluted atmosphere which causes environmental damage, reduced visibility and health concerns.

According to Reuters, in 2024, US railroads produced a combined total of 485,000 tonnes of nitrogen oxide, compared to US coal-fired plants which emitted 452,000 tonnes. At the helm of this, sits BNSF railway. 

As one of the largest freight networks in North America, it covers 32,500 miles of wail across the western two-thirds of the US. It also describes itself as an environmental leader, with the cleanest locomotive fleet in North America. 

"When you see our orange locomotives’ and freight cars’ steel wheels moving on steel rails, think green,” BNSF boasts in its latest sustainability review. Despite this, it accounts for approximately one thirds of the total nitrogen oxide emissions, producing 161,500 tonnes in 2024.

The company, however, does not dispute, explaining, "BNSF is the biggest Class I railroad by volume." Class I railroads refers to the six major railroads which have more than US$1bn in annual revenue.

Outdated logistics 

According to the EPA’s Co-Benefits Risk Assessment tool, pollution caused by railroad locomotives result in approximately US$48bn in healthcare costs and lead to 3,100 early deaths every year in the US. 

“Americans don’t realise how much harmful pollution comes from old diesel locomotives,” says Bill Magavern, Policy Director for the Coalition for Clean Air, a California group advocating for public health. 

“EPA should require the railroad companies to modernise their fleets."

Part of the issue lies in the aging fleet within the industry. According to EPA, the average age of US locomotives is 28 years, sitting at eight years older than figures in 2009. The older a locomotive is, the more emissions it will be producing, as it has not been updated to work on sustainable fuels and also lacks the fuel efficiency of more modern fleets.

As there are currently no requirements in retiring old fleets, the US freight industry is reluctant to invest in buying new vehicles. Due to federal emissions standards, older fleets have the more forgiving limits on them, whereas newer fleets are expected to meet higher standards, as they are coming into the industry with a more enlightened understanding of pollution. 

Senator Edward Markey, a Massachusetts Democrat, explains: "Our air pollution standards for railroads have an engine-sized loophole in them, which companies are using to... keep old, dirty trains on the tracks."

The rail industry is the most fuel efficient and cleanest option for land freight. One locomotive can transport a ton of freight across 500 miles per gallon, which is three or four times more efficient than trucks. However, to make a true difference, fleets need to be modernised.

Barriers to sustainability

BNSF states it is reducing its emissions through improvements to its technology and efficiency. Out of its 6,780 locomotives, 360 are modern ones which follow the Tier 4 federal emissions standards - the strictest level. From 2020 to 2024, BNSF spent US$394m on 165 new and rebuilt locomotives, which is down 69% from the previous fives years, when it spent US$1.26bn on 558 locomotives. 

Its fuel economy is the worst out of the Class I railroads. In 2024, BNSF burned 1.14 gallons of diesel for every ton of weight it moved 1,000 miles. In comparison, Union Pacific burned 1.08 gallons and Canadian National burned 0.88 gallons, for the same weight and distance. Despite this, BNSF maintains it is an industry leader in sustainability.

The rail industry is reluctant to adopt cleaner technologies and invest in Tier 4 fleets, due to concerns that these changes will be inefficient spending. Though the Tier 4 locomotives can significantly reduce NOx emissions, the widespread push for zero emissions will soon make these models out-of date. 

BNSF has also found that battery-electric locomotives are inefficient models which do not meet the capabilities required, particularly over long distances. 

"The battery had two megawatts of usable energy,” John Lovenburg, BNSF’s Vice President for Environment and Sustainability, comments. “That’s roughly 1/40th of the energy we will need for line-haul locomotives.”

Though they are suitable for shorter routes, they are not able to replace diesel locomotives across the required routes, as they are limited by battery weight. Across the industry, therefore, freight operators are facing more barriers to sustainable logistics than benefits.