A Defense of Diesel Locomotives

Modern transportation and technology has allowed us to buy a product online and have it delivered to our doorstep, even if it originated across the country. Behind this convenience is a network of highways, ports, warehouses, and railroads, which all work around the clock to keep the economy moving. Among the most important parts are freight trains. These stretch for several miles and carry the equivalent of hundreds of truckloads, transporting a wide range of goods. Though they often trundle along at less than 50 miles per hour, they play a crucial role in ensuring that the products we rely on are within reach.

The Importance of Freight Rail

Seemingly outdated and unimpressive freight trains slither across the US 24 hours a day. Altogether, the 140 thousand miles (225 km) of railroads move 28% of the country’s cargo by weight (FRA). That’s 1.7 trillion ton miles being carried by trains that are over 1 mile (1.6 km)

on average. The system contributed 233 billion USD to the overall economy in 2023, directly and indirectly supporting over 1 million jobs. According to the Association of American Railroads, every 1 dollar invested in rail transportation generates 2.50 dollars in return. But despite the fact that freight railroads have maintained their relevance in the American economy, today they are under attack for one main reason: the environment.

Status Quo Policies and Public Discourse

For how large and expansive it is, the American railroads are unlike any other because they seem to refuse any type of modernization. Whereas Europe and China have achieved 60 and 75 percent electrification respectively, the US sits at less than 1 percent, none of which has been used by cargo trains. The popularity of diesel-powered locomotives has prompted multiple waves of environmental regulations. For example, the Environmental Protection Agency (EPA) implemented Tier 4 standards in 2015, significantly reducing the amount of nitrogen oxides and particular matter emitted. Changes can also be seen in the passenger rail industry. Just last year, Metrolink purchased Stadler Rail’s FLIRT H2, a hydrogen-powered zero-emissions multiple unit. The agency has made it clear that it intends to eventually replace all of its diesels with hydrogen power, though the ability of the plan to uphold service capacity remains ambiguous. Additionally, some states have tried to take extra steps, with California attempting to fully implement zero-emission locomotives by 2035, an initiative that was blocked by the EPA’s withdrawal of a necessary waiver in January.

Still, federal regulations are expected to continue to close in on diesel emissions, yet the industry doesn’t seem to be moving. Instead of a race for electrification, environmental restrictions have prompted companies like ProgressRail and WABTEC to develop a new type of train: a battery-electric locomotive. But these designs are slow to implement. Although multiple freight companies have shown interest, battery-powered locomotives are currently unable to compete with diesels in terms of operational range and are riddled with technical issues. Given the industry’s slow pacing towards environmental reform, we must ask the question: are these emissions regulations really effective, or is there a better way to reduce America’s carbon footprint?

Rail vs. Road

Although anything powered by fossil fuels is portrayed in a negative light, not all vehicles produce emissions on the same scale, especially when considering the aggregate effects of an entire industry. The reality is that “dirty” diesel freight operations move over a quarter of America’s goods, all while only accounting for 2 percent of America’s transport-related emissions.

Trucks, on the other hand, can only dream of such efficiency. While road vehicles carry around half of the country’s goods, they also make up 28 percent of carbon emissions. This means that trucks can move 1.8 percent of freight for every 1 percent of greenhouse gases produced. What about trains? Over 14 percent of freight for the same amount of environmental footprint.

Science supports this conclusion, and it mostly has to do with friction: steel wheels on steel tracks are a combination with a much lower kinetic friction coefficient than rubber wheels on cement roads. In other words, less energy is dissipated as heat, meaning more can be used to actually move the load. In addition, long distance freight trains rarely have to stop and start back up again, mitigating the biggest source of fuel inefficiency (acceleration and deceleration). Statistically speaking, railroads are four times more energy efficient than trucks. TCWR quantifies that shipping by train consumes three times less fuel and cuts carbon emissions by 75 percent. Especially in the twenty-first century, where locomotives are more powerful and more efficient than ever, it is undeniable that trains are the superior way to move freight.

The Actual Solution

The fact of the matter is this: when it comes to environmentalism, the railroads, including diesel operations, are an ally, not a scapegoat. Policies that are targeted toward eliminating locomotive emissions upfront miss the point entirely. Just like how subways help drivers by indirectly reducing the number of car commuters, diesel freight rail actually benefits the environment by transporting goods that would have required extra trucks on the road. Even if America’s railroads produce some emissions, they will inevitably achieve a net reduction in greenhouse gases by being a direct replacement for less efficient road vehicles.

The country’s course of action should not necessarily be focused on directly decreasing the carbon footprint of freight operations, at least not in the way that the status quo has perpetuated. One option is to work towards electrification specifically, not just “zero emissions.” To be sure, railroad companies would not be thrilled with this decision. However, the EPA has already shown that it knows how to deal with a stubborn industry through its past policies. Instead of implementing drastic regulations all at once, the federal standards were pushed through in phases, allowing companies to rebuild their older locomotives to meet new laws, or purchase entirely new ones. In the same way, electrification could be pursued in phases. Not only would this result in cleaner operations, but it would allow the US to become an open market with a massive demand for new electric locomotives. Foreign companies like Stadler and Alstom will no doubt be interested, and domestic producers won’t be required to venture into uncharted territory like battery-electric propulsion.

But for a moment, let’s set aside the conversation about overhead wires and electric locomotives. Isn’t it a shame that only about a quarter of America’s freight is moved by the most energy efficient mode of transportation? It soon becomes very clear that although reducing direct emissions is a good idea, taking trucks off the road is an even better idea. The very vehicles that contribute the most to global warming are also the ones that we use the most to ship our goods. If the US were to focus on reducing its reliance on eighteen-wheeler trucks and shift priority to freight rail, the carbon savings would be immense, with or without diesel locomotives. Emphasizing rail is a myriad of possibilities, which will obviously require the federal government. For example, many rural communities have been cut off from freight trains due to a cost-saving measure known as precision scheduled railroading (PSR). Therefore, underserved areas must rely on road vehicles to transport goods, an option that is both more expensive and more polluting. Additionally, warehouse rail access is limited across the country, meaning that large plots of land need to be devoted to loading docks for trucks. Enabling more facilities to be connected by even just a basic single-track line decreases truck reliance significantly, as freight train capacity is highly scalable and responds easily to demand (a characteristic that is hard to replicate amongst trailer trucks).

Conclusion

I do not deny the advancements that regulations have made in the world of diesel locomotives. After all, trains are only as clean as they are today because of such laws. I also do not deny that the environment very much needs to be protected. But it is for this reason specifically that I am not an outright opponent of diesel power: because a diesel train is still a train. And a train will be many times more efficient than whatever is found on freeways and roads. Yes, diesels have their disadvantages. For instance, I am a firm believer that most American commuter rail services should replace their aging fleets with electric multiple units powered by overhead wires. However, when it comes to freight transport, we must examine the issue of climate change in the context of the railroads. In other words, “diesel” is not a blanket term for something that must be eliminated to save the environment.

Effective environmental policy should focus not just on reducing emissions from individual vehicles, but also on encouraging the most efficient ways to move our goods. We should not let the image of perfection stop us from progress. As we work toward a lower-carbon future, preserving and strengthening rail transportation may be one of the most impactful steps we take.