Abstract: China's railway to Tibet is an engineering marvel or an environmental menace — or perhaps both. Jane Qiu takes a ride to find out. The Qinghai–Tibet railway, linking Golmud in China's Qinghai province to Lhasa, is the world's highest railway: it reaches more than 5,000 metres above sea level as it runs through the Tanggula Pass. It's an engineering marvel. But are the environmental costs justifiable? Jane Qiu talked to proponents and opponents of the line — and went along for the ride.