By rail to the roof of the world

No, this isn't another model railroad posting, but a link to an article from Wired (of all places) describing the Qinghai-Tibet Railway, a recently-constructed railway in China. It's described as the highest railroad in the world, much of it over 13,000 feet elevation. It includes some fascinating details about the unusual challenges that the builders had to overcome, and the adaptations they had to make.