Why extreme heat can buckle Metro rails near College Park

Extreme heat can turn a routine Metro ride into a safety problem in Prince George’s County, and the July 4 derailment near College Park made that risk visible in one afternoon. A six-car train came off the tracks around 11:50 a.m. between Hyattsville Crossing station and College Park station, forcing 11 passengers to evacuate and sending one adult male to a hospital for evaluation while another declined treatment; Metro said no serious injuries were reported.

What happened near College Park

The incident immediately disrupted Green Line and Yellow Line service, which was reduced to a single track after the derailment. That meant the problem was not confined to the stretch of track where the train left the rails; it slowed the broader corridor that many County riders use to move through southern Prince George’s County and into the District.

Metro later said it was investigating a “potential heat-related track issue,” and investigators focused on a rail heat kink, the kind of bending that can happen when steel gets too hot and loses its shape. Prince George’s County Fire and EMS Department and other responders handled the evacuation at the scene, while riders were left to wait for a rail system that had already been strained by holiday traffic.

How heat can buckle steel rail

The science behind a heat kink is straightforward, even if the consequences are not. Steel expands when it heats up, and on a sunny day the rail itself can get much hotter than the air around it. If that expanding metal has nowhere to go, the track can bow or shift sideways, creating a sun kink or heat kink.

That matters because trains are heavy enough to force their way over a rail that is no longer perfectly aligned. Once the track shifts, a train can come off the rail instead of staying on it. In practical terms, the hazard is not just a maintenance issue buried in the right of way; it is a direct threat to safe movement on exposed sections of the system.

Metro’s own guidance says rail temperatures can reach 135 degrees or higher in direct sunlight and high ambient heat. That is the threshold that makes the rail itself a safety concern, not just the weather outside the train window.

What Metro says it does when temperatures spike

Metro has built a heat response around slowing trains and watching the tracks more closely. When inspectors detect rail temperatures above 135 degrees, the agency says a slow order goes into effect. Metro also limits above-ground train speeds to 35 mph during extreme heat, a precaution meant to reduce stress on the rail and give operators more time to react if something shifts.

The agency says it adds inspectors and supervisors during hot spells to walk and ride the system looking for heat-related issues. That is the operational answer to a problem that can develop quickly on exposed track, especially where rails sit in direct sun for hours at a time.

Metro has also tested a lower-tech fix on some above-ground segments: reflective white paint. The idea is simple enough for riders to understand. If the rail reflects more sunlight and holds less heat, it is less likely to reach the temperatures that trigger a buckle.

What riders in Prince George’s County should expect

For people riding through College Park, Hyattsville, and the rest of the Green and Yellow Line corridor, the most immediate impact of extreme heat is slower service and longer trips. Slow orders reduce speed on purpose, and that means even a train that stays on schedule can reach a destination later than usual.

The July 4 derailment also landed on a day when Metro had already announced holiday service changes and free fares after 5 p.m. for Independence Day travel. More service was planned for crowds headed to fireworks and other celebrations, but the derailment showed how quickly the system can shift from holiday readiness to disruption once heat and rail conditions collide.

That is why summer rail reliability matters so much in Prince George’s County. The line between a manageable delay and a major service disruption can be thin when temperatures climb, especially on track sections that are above ground and exposed to the full force of the sun.

Why this is not a one-time problem

Metro has faced the same failure mode before. In July 2012, the agency said investigators determined that a misalignment of the rails, known as a “heat kink,” was the probable cause of a derailment near West Hyattsville Station, where three cars derailed as a Green Line train entered a tunnel from an outdoor section of track.

That history matters because it shows the College Park derailment fits a known pattern, not an unexplained one-off. Metro knows rail heat is a recurring summer risk. It has slow orders, extra inspections, and reflective paint in its toolbox because the hazard is real and predictable.

The accountability question now is whether those safeguards are enough for the hottest days of the season, and whether Prince George’s County riders should expect more slowdowns before summer ends. The derailment near College Park suggests the answer is already being written in real time on the rails themselves.