Extreme heat is increasingly threatening public transit systems, considered a highly effective way to reduce carbon emissions and progress toward clean transportation goals.
Civil engineers and mass transit authorities warn that railroads or tracks could bend or buckle under the extreme heat.
To mitigate the risks, speed restrictions and even rail service suspension are being issue on some of the hottest days.
Extreme weather may lead to more transit service disruptions as agencies avert damages and make repairs.
In June, 2022 the San Francisco Bay Area Rapid Transit (BART) cited -- for the first time -- extreme heat “causing a curve in the rail” as “the main role in the partial train derailment.” As ambient air temperature reached a high of 102˚ F (39˚ C), the rail tracks likely reached 140˚ F (60˚ C) — 25 degrees hotter than what the mass transit authority considers safe.
In June, 2021 extreme heat melted cables that power Portland, Oregon’s TriMet light rail system. The U.S. National Weather Service (NWS) reported an ambient air temperature of 112˚ F (44˚ C). All train services were suspended for two days since the “system is designed to operate in up to 110˚ F (43˚ C) heat.”
In the U.K. as national heat records have been shattered, Network Rail has painted railways white in some areas in an effort to deflect the heat and prevent warping. In Vauxhall, London, unpainted tracks warped as the they reached a temperature of 118˚ F (48˚ C). In direct sunshine, railways can become as much as 20 degrees hotter than the ambient air temperature.
Nationwide, passengers have been advised to avoid all unessential travel and train services have been cut.