When temperatures climbed into the upper 90s during early September, the Maryland Transit Administration tweeted out that Metro and Light RailLink trains would be running at reduced speeds due to extreme heat.

The reductions in the maximum allowable speed were necessary “in order to maintain safe operating conditions,” the agency said.

But why do trains have to go slower when it’s so hot outside? Because steel — the backbone of our railroads — expands when it heats.

“If I weld that piece of steel into the track, I’ve locked that piece of rail into track. So when it gets hot and it wants to expand, it has nowhere to go,” said Allan Zarembski, a professor and director of the Railway Engineering and Safety Program at the University of Delaware. “The constrained expansion turns into stress or force, so in fact what happens in hot weather is a compressive force that’s built up into that rail.”

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And what happens when the line of welded steel can’t hold against so much force?

“There’s a risk of a phenomenon called buckling, where the whole track literally snaps out to the side and causes a variation in geometry,” said Zarembski.

Can a train run when the track isn’t straight? The answer is a pretty straightforward no.

As heat records continue to be broken each year and climate change drives more extreme weather, rail engineers have the formidable task of safeguarding trains and their tracks from climate-induced tragedy. Like in Vermont earlier this summer, when flooding left train tracks suspended more than 100 feet in the air, sometimes extreme weather wins. And as last February’s fiery derailment of a freight train carrying hazardous chemicals in East Palestine, Ohio, recently showed, derailments can have devastating consequences. But Zarembski thinks the industry is up to the task.

Extreme heat isn’t the only challenge. Colder air temperatures cause steel to contract, leading to the opposite of a track buckle, known in the industry as a “pull-apart” — two sections of steel track that literally detach from one another. Zarembski said most rail operators build sensors into the track that can detect pull-aparts, notifying mechanics that work is necessary.

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“The problem with track buckles is that you have no way to know that it happens,” Zarembski said. Even though the track gets disfigured, he said, “the rail stays continuous” — meaning the sensors indicating a problem don’t get tripped.

Mechanics and engineers at the MTA, though, say they are prepared to deal with this. Temperatures of 90 degrees or above automatically trigger heat inspections for the city’s Metro and light rail systems, according to Paul Shepard, a spokesperson for the MTA. And slowing the trains means less pressure on the steel track, which in turns means less force that might create a buckle.

Power substations and central instrument houses for Metro and light rail are also mostly temperature-controlled, Shepard said. And rail switch points — sections of curved track that move to guide trains onto a different track — are stocked with heaters that melt snow and ice.

Amtrak is on board with these measures, too.

Beth Toll, senior public relations manager for the national passenger rail company, said it installed temperature gauges every 25 miles along the Northeast Corridor’s rail lines. Those gauges let Amtrak know when it has to impose speed restrictions, too.

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Slower speeds also allow train operators to spot track buckles ahead, Zarembski noted. When operators see it too late and have to slam on the brakes, it puts even more force on the track, making the rail kink even bigger.

Regulating rail

The United States is home to roughly 140,000 miles of freight rail line alone — enough to wrap around the earth’s circumference nearly six times — according to the Association of American Railroads, or AAR. Though Amtrak utilizes rail owned by private freight companies throughout most of the country, it does own more than 500 miles of track in the eastern U.S.

Maryland’s rail network consists of roughly 886 miles, according to the 2022 state rail plan.

All operators, from Amtrak to CSX to small excursion rail lines, like Cumberland’s Western Maryland Scenic Railroad, must adhere to a slew of safety standards and regulations laid out by the Federal Railroad Administration. These include specifications for speed, the shapes of track turns and more, and vary depending on factors like weather conditions and the type of cargo a train carries.

Three state-employed inspectors walk or ride all 886 miles of rail track at least once a year — a “tall order,” according to a railroad administrative officer from the Maryland Department of Labor, Licensing and Regulation, which monitors rail company compliance with federal regulations.

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Defects get written up and reinspected within 30 days, a department spokesperson said in an emailed statement, and more serious violations can result in fines for a rail company.

But with so much track to cover, federal and state governments often rely on companies to be thorough and diligent with their own inspections for tracks, trains and other rail assets, according to an FRA spokesperson.

“FRA’s primary safety responsibility is to audit railroads’ safety performance and activities, which includes ensuring that their inspection frequency meets or exceeds minimums set forth in federal regulations,” the spokesperson said in an emailed statement.

The AAR estimates that 67% of all freight rail miles are run by the six companies. CSX Transportation and Norfolk Southern Railway are the only Class I companies that operate in Maryland.

Norfolk Southern was at the center of safety scrutiny earlier this year after one of its trains carrying toxic chemicals derailed in East Palestine, Ohio, forcing local residents to evacuate their homes. A preliminary investigation from the National Transportation Safety Board blamed the derailment on an overheated axle bearing, not overheating rail.

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Then in March, the freight rail industry committed to new safety measures, including more training on accident mitigation and new guidelines around hot bearing detectors.

Climate concerns are not driving any talk of increased regulation or safety scrutiny, but track buckling and pull-aparts “have always been a major concern and always will be regardless of hotter temperatures or increased risk of severe weather,” said a railroad administrator with the state labor department.

But the department emphasized that it’s in the best interest of rail companies to keep their tracks in tip-top shape, as poor track conditions and derailments ultimately affect their bottom lines.

And there are fixes for the temperature issue, Zarembski said, but not necessarily simple ones. The key factor is how hot the steel rail is in comparison to ambient temperature, Zarembski explained, and the temperature at the time track gets installed sets the gauge.

“So if you know that temperatures are increasing, you are going to start raising your installation temperatures,” he said. “That’s going to increase your risk of pull-apart at the cold end, but that, as I said, tends to be less of a safety concern — it’s a big maintenance headache, and then you’re going to have to deal with it. But you can deal with maintenance headaches more than you can deal with safety issues.”

Zarembski also noted that the railroad industry is constantly in conversation with itself, both nationally and at the global level. If it can run trains through the Mojave desert and some of the coldest parts of Russia, he said, then keeping the trains chugging into the future is a task the industry is prepared for.

Daniel Zawodny covers transportation for The Baltimore Banner as a corps member with Report For America, a national service organization that places emerging journalists with local newsrooms that cover underreported issues.


Daniel Zawodny covers transportation for the The Baltimore Banner as a corps member with Report For America. He is a Baltimore area native and graduated with his master's degree in journalism from American University in 2021. He is bilingual in English and Spanish and previously covered immigration issues.

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