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From the article: The researchers found that the rubbing of metal wheels and brakes on the rails releases metal particles, which appear in particular concentra
by arbuge 2y ago
From the article:
The researchers found that the rubbing of metal wheels and brakes on the rails releases metal particles, which appear in particular concentrations as the trains arrive at a station.
“We noticed that when a train arrives at the station, the concentration in the air shoots up, and about 15-20 seconds after it leaves, the concentration slowly comes down,” said Ghandehari. “This implies that it is the stuff that’s at the bottom of the tunnel that gets churned up and deteriorates the air.”
- amluto 2y agoRight, so they covered lots of bases. But they didn’t actually discuss how much of the pollution came from each source, and they didn’t address why the brakes are being applied. Most modern EVs can come to a near stop using regenerative braking without applying mechanical brakes at all. Some motor controller software could surely bring it to a complete stop with minimal or no hardware changes. (If you find a safe place with no obstacles, you can generally stop a car, EV or otherwise, by driving slowly forward, shifting to reverse, and stepping gently on the accelerator. In a car with a conventional engine, this involve friction internal to the clutch or torque converter. In an EV, it’s the motor applying torque opposite to its direction of rotation.) A subway train quite similar to an EV.