(Marvin Joseph/The Washington Post)

Q: It’s not a really a question, but a Metro train operator emailed us because he wants riders to know he has no control over the air conditioning in the cars. “We cannot turn it off, on, low or high,” he wrote.

A: That’s true. Each car in the train has its own HVAC system that, in the newest trains, goes on when it’s over 75 degrees inside and turns off when it cools down to about 71 or 72 degrees. But the system can only cool the cars by 20 degrees, so if it’s a 100-degree day, the cars will only get down to about 80.

Train manufacturers we contacted declined to say if they make trains that allow conductors to adjust the temperature. But spokespeople for New York’s Metropolitan Transportation Authority and San Francisco’s Bay Area Rapid Transit say the air conditioning on their trains works the same way.

Metro says it’s made progress in preventing “hot cars.” In fact, according to Metro’s figures, hot-car incidents dropped from 243 in June of 2016 to 97 this June.

While Metro has reduced hot cars, the numbers likely overstate the progress because they don’t account for the fact that Metro is running fewer trains overall because of its 2017 service reductions, said James Pizzurro of Rail Transit OPS, which monitors Metro service and partners with @DCMetroHero to tweet updates.

If your car is hot, Metro says you should contact the train operator using the intercom. The operator will notify Metro’s control center, and someone will meet the train on its route to try to fix it. Then, do what most people do: Try another car at the next stop, because, yes, each one operates on its own HVAC system.

Let us know what frustrates or confounds you about Metro. Reach us at kery.murakami@washpost.com or @theDCrider.

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