"Extreme" rail travel?

You don't normally pay extra for these kinds of thrills:

Pens leaked. Air-tight bags of crisps and peanuts burst open. Laptops crashed and MP3 players stopped working. Passengers began feeling nauseous, and some reached for their oxygen masks. A few were sick.

But few of the 500 passengers on board were complaining. For railway buffs, this was as close as it came to paradise. We were on board the first passenger train to journey the 4,000km (2,500 miles) from Beijing to the ancient Tibetan capital of Lhasa and the final 1,110km yesterday took us up through the 5,072m (16,640ft) Tanggula Pass and across the roof of the world.

Hat tip to Phil Clark for the URL.