h1

High mix : oxygen on the Tibet train

December 23, 2008

Oxygen is supplied in two ways on the Beijing-Lhasa train . The visible hardware is the oxygen outlets placed under seats , and on the walls in compartments and corridors. Double pronged soft nasal cannulas (not the most efficient delivery , but somewhat more comfortable ) are used with

these.

o2final

The invisible part is the extra oxygen that is added directly in to the air of the compartments, to a concentation between 24-25 % .

screen-capture-21

Oxygen pressure at different elevations at 21 % and 24 % (measured by John B West , 24.1 -25.3 %, see the Revisited .. post)

The only figure that relates directly to how how much oxygen there is in what we inhale is the oxygen (partial ) pressure . One fifth of air is oxygen , this means 21 kilopascal at sea level. At the highest point along the train ride , Tangula pass at 5076 meters the ambient oxygen pressure has been reduced to 11 kPa but inhaling 24 % oxygen(upper curve)  instead means that you inhale the same amount of oxygen as on  a  lower elevation. At Nakchu , 4500 meters , you will actually be marginally better  off than in Lhasa.

Oxygen is added from Golmud (2800 meters) and onwards. The oxygen is produced by oxygen generators that separate the nitrogen and bleed the oxygen into  the compartments. This is the same technology that has been used for a number of years in for example Chajnantor Observatory , one of the worlds highest civilian workplaces at 5050 meters. 

Using the supplementary oxygen lines : 

The main advantages of taking the train lies in the time spent between Xining and Golmud (2400-3000-2800) , after that conditions are very close to being at Lhasa´s altitude. Most , but not all , handle coming up to Lhasa´s altitude without  any major problems after a intermediate stop but I have for example met one person with early stages of altitude sickness in Tabo , some four hundred meters lower than Lhasa.

Use the oxygen lines if you have any symptoms of hypoxia , i.e. always if  you have headaches. Oxygen saturation in the blood will always drop as you lie down, if you had any symtoms during the day you will at least sleep better with oxygen.

About these ads

2 comments

  1. Hi

    Thanks for this. Very interesting. Does it work though? I am taking the train in Feb and have had altitude sickness before. This doesn’t obviously say that I will have it again – but still I’d need to know the definite risks. What about medication on board? Useless or not – I have heard there is a doctor? And does Lhasa have pressure cabins? Thanks for any info!


  2. Does it work ? In the sense that breathing higher oxygen concentration eliminates altitude symtoms : unreservedly yes. Are they able to maintain these concentrations ? That comes down to the combination of the technical system and the people handling it. I had misgiving over this , like what happens when they open the doors at high elevation stations. The answer seems to be ( see Tibet Train Revisited) that they don´t open them , or open very sparingly , everyone has to get out through one or two doors. This of course can come out differently on different runs , different crews. Passengers in hard class are more vulnerable here , since there are no separated compartments with doors.

    On the other hand the combination of both higher concentration in the cabin air and oxygen cannulas should give a large safety margin on the train ride.

    Your best preparation before the train is nights spent above 2000. This gives you two alternatives : Xining at 2400 ( somrwhat higher than cabin pressure on a plane ) and Golmud at 2800. Three nights near three thousand gives for most people the first very important step in acclimatization , very few fall outside the two to five nights range. Theoretically you could go for one night each in Xining and Golmud , the train being the third , but few seem to have anything warm to say about Golmud.

    Personally I would make sure to make at least a overnight stay in Xining to tweak altitude adaption , and welcome the chance to make forays in the area. The area is steeped in Tibetan culture and history ,once being a Tibetan border town. The present Dalai Lama was born in the area , the sixth died (probably murdered by Mongol troops ) at Koko Nor/Qinhai Lake close to Xining , at 3000 meters. Try http://kekexili.typepad.com if you find this interesting. Time spent on the train before Xining is irrelevant in acclimatiztion , if flying Beijing-Xining neans an extra night there , go for it.

    As for your previous history with altitude sickness my first reaction to this is : good . You have been through it , say so , which means that you are able to act on early signs , not being in denial. With at least a night in Xining I think it´s overkill to medicate preventively . Take extra oxygen if you get headaches , and consider oxygen when sleeping, this should not be worse than going up to 3000 with a intermediate stop.

    Treatment in Lhasa etc. : first reaction would be descent , unfortunately I don´t think there is any easily available location below Lhasa´s altitude near by , certainly not wetstwards where I came from. Announced plans talks of a rail coonection between Lhasa and Nyingchi, NE of Assam at 3000 meters , that would be a fallback option or a softer run to Lhasa.
    Hospital treatment would be oxygen and Diamox from what I´ve seen in litterature.Huge amounts of money and resources (including helicopter evacs ) were put in place for the railroad workers , but they used the same concept as on the train , with both oxygen bars and tents with ambient pressure and higher oxygen concentration. Gamow bags , the portable pressure chambers made of fabric used by Western climbers seems to be almost unknown in Tibet and China. Pressure chamber in Lhasa … don´t know , don´t think it would be available for anything but very dramatic cases (climbers etc. ). For train passengers I think the concept would be in 90 % of the cases oxygen , some medication – and a flight out in some very rare cases.



Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 72 other followers

%d bloggers like this: