Since I’ve been in London, I’ve noticed that there during certain parts of the tube ride, my ears start hurting like hell and I have to pop them. In particular, it seems to happen on the District/Circle line between South Kensington and Sloane Square stations. I figured that part of the track just dipped a lot and the elevation change was making my ears go wonky. Then today, I took the train out to Cambridge, and whenever we went though tunnels, I had that same vertigo-y pain in my ears and felt the urgent need to pop them.
So, what could be causing this? Do all of the tunnels have rapid changes in elevation that are doing this? I’m actually thinking that there’s some interaction between the tunnel and the rapidly moving train that’s causing a change in the air pressure, but I can’t quite work out the mechanics. Any thoughts?
It’s not changes in elevation, it’s changes in pressure. Depending on how the tunnels are constructed, when a train enters the air pressure in the cars could increase due to the fact that the train is pushing/displacing a lot of air and it has no place to go.
Telemark got it. A train travelling in the open has everywhere to displace the air it moves as it travels, but once it enters a tunnel, all that air is still getting displaced, but suddenly it has nowhere else to go, so it kind of gets “compressed,” thus increasing the air pressure inside the train cars.
Toronto’s subway station had/has (been a while) a few tunnels that were particularly bad because they’re round, which presents an even tighter fit for trains travelling through them, which means even higher air pressure (though not by much).
This can happen even after a train has just entered a tunnel and has already come to a complete stop! On my way from Chiusi to Rome this occurred after, for whatever reason, our train had come to a complete stop in a tunnel, and had been at a complete stop, when all of a sudden my ears started pressurizing something awful! I was really panicking unable to understand what in the world was going on, with the added stress of being completely surrounded in darkness. It’s the whole reason I found this forum trying to find answers.
It’s been nearly nine years. Is your train out of the tunnel yet?
For a detailed explanation, see piston effect. This is a significant issue for high-speed trains. Japan’s Shinkansen trains literally seal the doors in order to avoid problematic increases in cabin pressure when entering/exiting tunnels. It’s less of an issue in places like Europe, where high-speed trained were installed later; designers were aware of this problem due to Japan’s experiences, and they made the tunnels larger to help mitigate the problem.
Oddly enough, my ears also pop when the train goes through a tunnel. This is odd because I don’t ride the train, and the nearest tunnel is probably at least 2 or 3 hundred miles away.
