Eli5: Why do high speed trains pressurize the cabin?
In: Engineering
Air around a high speed object also moves fast. Faster air movement means lower pressure. If air around the train has lower pressure, air inside the train will leak out until pressure equalises. If the train is moving fast enough, people can get discomfort from the lower pressure so they pressurize to prevent it.
The faster a train goes through a tunnel the more pressure it creates, having the cabin pressurized means the passengers don’t feel the change in pressure.
One response saying the speed would increase the pressure on the cabin, another saying it would decrease pressure in the cabin.
Answer: they’re all sealed to minimize pressure changes in the cabin. Some are pressurized some aren’t. The external pressure definitely increases when going into a tunnels for example.
So there’s a component of minimizing pressure changes for the passengers, but also just maintaining the structural stability of the car with sudden external pressure changes.
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