Twenty years ago, a railway pushed the boundaries of engineering across the Qinghai-Xizang Plateau, crossing some of the world’s highest and most challenging terrain. What was once considered impossible became reality, the Qinghai-Xizang Railway. Starting today, CGTN launches "Beyond the Tracks", a five-part series exploring the life-changing transformations and human stories along the world’s highest and longest plateau railway. Behind the profound changes the railway has brought to local communities are the technological innovations that turned the impossible into reality. Xu Xinchen travels to an altitude of more than 4,700 meters to find out more.