China has announced the completion of the first railway line from Golmud in China's north-western province of Qinghai to Lhasa, in Tibet. The line is expected to start taking passengers in 2006. This is one of the world's highest train routes, at 5,072m (16,640ft) above sea level. Trains travelling on the line will have to have carriages that are sealed like aircraft to protect passengers from altitude sickness. The workers who built the line had to breathe bottled oxygen in order to deal with the high altitudes.