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First Beijing train reaches Lhasa -- Why Oxygen on it? That makes no sense to me. The problem at elevation isn't the oxygen.

By Andrew Pollack on 07/03/2006 at 09:20 PM EDT

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.

http://news.bbc.co.uk/2/hi/asia-pacific/5140514.stm

There are - loading - comments....

I would guess it's a matter of economicsBy Richard Schwartz on 07/04/2006 at 12:35 AM EDT

I would guess that the train is at a low enough altitude most of the time that
neither 02 nor pressurized cabin is needed. A system capable of delivering 02
for the periods of time that the train is at high enough altitude to need it is
readily available. Railroad cars with pressurized cabins would have to be
specially designed, built, and maintained.

methinksBy Craig Wiseman on 07/05/2006 at 10:35 PM EDT

The fireman is thinking about how much damage an O2 leak could do.....

Poof! goodbye train....

From all accounts, oxigen was the least of their problems!By Ian Randall on 07/09/2006 at 06:45 PM EDT

I recollect recently hearing a National Geographic story on the building of
this rail line.

Apparently a great many (several hundred) workers involved in constructing of
the Beijing to Lhasa rail line lost their lives.

But then, it's construction was motivated more by public relations and military
objectives more than than tourism , so the massive loss of life was probably
justified as an acceptible cost by the Chinese Government.

Also, it's construction bolsters the Chinese Governments claims of soverenty
over Tibet, so no cost would have been seen as too high.

OxygenBy brianorca on 07/13/2006 at 05:26 PM EDT

Oxygen actually is the problem with low pressure. We need a "partial pressure"
of 3psi of oxygen to breath. That can be in the form of 20% of the 15psi we get
at sea level, or 40% of the 8psi you might find at 14,000 ft. The astronauts,
when wearing a space suit, actually breath pure oxygen at only 4.5psi.

3psi of oxygen is not any more flamable than the mix we breath at sea level.

The previous poster also had some good points about the technical requirements
(hardware and maintenance) of a presurized train.

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First Beijing train reaches Lhasa -- Why Oxygen on it? That makes no sense to me. The problem at elevation isn't the oxygen.

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