Decarbonizing diesel-powered locomotives, one of the Biden administration’s climate policy goals, will require major investments in a fleet of engines using an as-yet undetermined alternative power source.

The lack of consensus over how to power these new trains could put President Joe Biden’s emissions targets out of reach, analysts say.

Although rail is typically hailed as a greener mode of transportation — it made up only about 2 percent of emissions from the transportation sector in 2022, compared with 57 percent from light-duty vehicles — the Biden administration is still targeting the “hard to decarbonize” transportation mode.

All of the largest railroad operators have announced climate goals, and some plan to eventually scale up alternative-fuel locomotives. But the industry has yet to pick one — battery electric, hydrogen and catenary electric are among the choices — that will give it the most bang for its buck.

Canadian Pacific Kansas City, for example, introduced its first hydrogen-powered locomotive in 2022, and it now has a small fleet of low-horsepower models running out of its terminal in Calgary, Alberta. Likewise, CSX in April unveiled its own hydrogen model, a former diesel train altered using a hydrogen conversion kit developed by Canadian Pacific, which is being deployed for field testing.

Railroads have also dabbled in electric power. Norfolk Southern introduced an electric locomotive in 2007, but despite the battery being revamped in 2014, the vehicle didn’t meet the company’s requirements and the project was later dropped. 

Locomotive manufacturer Wabtec partnered with BNSF to announce a battery-electric locomotive for testing in 2021, and Progress Rail, another manufacturer, said in 2022 it was supplying BNSF with four of its electric locomotives by this year.

The Biden administration goal is for the industry to “demonstrate” a 50 percent reduction in greenhouse gas emissions in a locomotive engine by 2030. That’s a long way from true deployment, rail experts caution.

“Demonstrating with hydrogen by 2030 or even with batteries can be done by 2030. But there is also a difference between demonstrating and everyday use,” said Mark Duve, a former Norfolk Southern engineer and current director of locomotive engineering at Higher Power Industries. “Locomotives tend to break down easily if not designed properly for everyday endurance.”

That means the bigger task — the White House goal of net-zero emissions from the transportation sector, including freight rail, by 2050 — is at risk.

No clear path

Because of the way railroads operate — frequently running a locomotive from one railroad on another’s line, often across international borders — railroads must reach consensus on an alternative fuel if they’re to have a homogeneous infrastructure.

“The technical challenge of getting a locomotive to run on a hydrogen fuel cell, a battery electric and so on is completely obtainable,” said Michael Cleveland, director of rail strategy at Peaker Services. “The bigger challenge is the logistics of getting that into the whole network.”

Each choice has its own share of challenges and costs.

Duve said electric locomotives with catenary, a system of overhead wires that supplies electricity to trains, are promising, but the infrastructure investment required has been a nonstarter for railroads. Large railroads were exploring battery locomotives aided by catenary infrastructure in certain areas, but the mode is still considered untested.

Battery electric locomotives, meanwhile, lack the “energy density” to pull the train long-term, according to experts. Duve said the Wabtec battery electric locomotive has one-tenth the usable energy compared with a full diesel tank. It also may take hours to charge a battery electric locomotive, whereas it takes less than 20 minutes to fuel a diesel.

Cleveland said the energy density for hydrogen-powered locomotives is also not as good as diesel, so trains would have to carry extra tanks with them in the form of tenders, which are still in their infancy.

Duve added that it would take a couple of years to figure out logistics for those tenders, as railroads would have to store hydrogen as a compressed gas, which would require safety analysis, training, testing and approval by the Federal Railroad Administration.

Hydrogen fuel is more expensive per gallon than diesel, he said, and most commercially usable hydrogen isn’t made sustainably.

Railroads have been investing heavily in biodiesel blends to cut down on emissions without requiring a large front investment in infrastructure, Cleveland said. He noted, however, that it’s only a short-term solution, as availability could get tricky as other transportation sectors vie for the same biodiesel.

Incremental improvement

The Association for American Railroads has argued against any “prescriptive” means for reducing rail emissions. Last year it encouraged a transition to zero-emission technologies when it’s “commercially viable and operationally safe and reliable.”

Large railroads have, however, increased their engagement with the federal government on new decarbonization technologies and are running cost-benefit analyses, according to an FRA official speaking on condition of anonymity. The official predicted that railroads will come to a consensus on an alternative-fuel technology within the next few years.

Still, emissions reductions so far have been small, said Wayne Kennedy, a veteran of Union Pacific Railroad who now consults railroads on fuel conservation and emissions reduction. Over the past 20 years, railroads have averaged a roughly 1 percent improvement in fuel efficiency annually, mostly through small measures like updating to new locomotives and cutting down on idle time, he said in an interview.

To meet a net-zero target by 2050, railroads would have to start making major investments soon.

“I used to work for GE transportation systems, now Wabtec … and a really fantastic year for them would be building maybe 1,000 locomotives a year,” he said. “And there’s 30,000 locomotives plying the rails throughout North America.”

Kennedy said railroads can be finicky about proving a technology’s fuel efficiency. A technology could result in 2 percent of fuel savings, which is roughly $100 million in cost savings a year. But if the railroads can’t definitively prove that savings will arrive, they are hesitant to invest in the technology, he said.

“There are a lot of technologies out there that save in the 1, 2, maybe even 3 percent range that railroads say, ‘Well, I haven’t been able to prove it, because maybe my fuel gauges aren’t as accurate as I need [them] to be, or I don’t have a dozen statisticians poring over the data to figure out exactly what’s going on,’” Kennedy added.

And some rail experts are still uncertain that railroads are ready to meaningfully invest in the switch.

“That’s the reason why they spoke out against catenary electrification, is because of the capital expenditures,” Duve said. “They’re going to do these experiments with hydrogen, but I don’t see them moving forward on it right now.”