Xining is 7000' and Golmud a bit more than 10000' (Metric conversion is left as an exercise)

The time was well spent since I normally life at 0 to 500' And its the time as well as the difference in altitude.

We spent 5 days in Lhasa (12000') before heading off to Everest Base Camp (+-17000') Even so walking up the smallish hills was noticably more effort than expected. Even for the 30 somethings that I was traveling with.

Bottles of oxygen were available for about AU$5. Didn't use mine. And there was a Chinese herbal remedy that was highly recommended (good for headache as well) and I did take that.

Even if you take the train stop in Xining for a few days. It's much larger than Golmud. Though the night market in Golmud was an interesting visit. Both are on the main line to Lhasa. You'll just need separate tickets for each segment.

Happy wandering

Fred