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So this train goes from Beijing to Lhasa -- covering permafrost and mountains. It peaks over 16,000 feet. I've been as high as 12,000 feet and hiked around a bit without getting too tired, but I was younger and I'd imagine that extra altitude could really do a person in. So, the Chinese built the train with onboard oxygen. This makes no sense to me.
The problem at altitude isn't lake of oxygen per se. Its lack of pressure. The amount of oxygen as a percentage is the same, but with reduced pressure, less is able to cross the membrane in our lungs and get into the bloodstream. (reference). On airplanes at 40,000 feet they are not pumping oxygen into the cabin. The will do so in an emergency only if the plane cannot contain cabin pressure. Why do you suppose that is? Does it cost less? No. The issue is that it doesn't help as much, and at the same time oxygen is very dangerous stuff. A few percent more than normal and something as innocent as a cigarette lighter can become a real problem. It is corrosive (it is, after all, an oxidizer) and highly flammable.
What I don't get then, is why go to the expense of adding oxygen distribution equipment to the train like that rather than simply pressurizing the cabin? If not everyone needs it, perhaps just pressurize a few cabins -- or provide a pressure mask for positive pressure breathing.
Someone who's seen a documentary on this strange train should post a comment and clue me in.
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