Which railway carries the highest-altitude passenger train in the world to Tibet?

The Qinghai–Tibet railway carries passenger trains to Tibet and is the world’s highest railway by elevation.

The line connects Xining in Qinghai province with Lhasa, the capital of the Tibet Autonomous Region. It opened in stages, with the final section to Lhasa beginning service in 2006. The railway crosses the Tibetan Plateau and reaches 5,068 metres above sea level at Tanggula Pass, the highest point on any railway.

High altitude creates special engineering and health challenges. Passenger carriages use oxygen systems, and trains are designed for harsh cold, permafrost and thin air. Much of the route crosses remote plateau landscapes with limited infrastructure.

The railway is sometimes called the Qinghai–Tibet or Qingzang railway. It is not the proposed Sichuan–Tibet railway, which is a separate planned route. The line’s engineering achievements are notable, but its construction and environmental effects have also been subjects of public discussion.