From the article:

As warmer temperatures return, Union Pacific is applying an innovative concept to manage heat-related track conditions – part of a broader strategy that helped the railroad deliver its best-ever full-year derailment incident rate in 2025, improving 19% year over year.

“Steel rails expand in extreme heat,” said Rod Doerr, chief safety officer. “When that steel has nowhere to go, it can push sideways and create what we call a thermal misalignment.”

[...]

“We took a page from road striping,” Doerr said. “Using a high-rail truck and paint sprayer, we apply white paint to both sides of the rail.”

The idea is simple: by reflecting sunlight, the white paint lowers the rail’s surface temperature.

“We’ve seen about a 20-degree drop in the rail temperature,” Doerr said. “That’s huge. If you’re not fighting the sun’s heat, you dramatically reduce the risk of the rail shifting.”

Union Pacific began targeted deployment in high-heat areas last year, adding another layer of protection alongside existing maintenance and inspection practices.

[...]

“When people first saw it, they said, ‘Why haven’t we been doing this for a hundred years?’” Doerr said. “That’s the kind of question I love to hear, because it means the culture of safety innovation is alive and well.”