Trains Crossing the "Stairway to Heaven"

　　

      On April 24, four days after the Grain Rain solar term, the Qinghai-Tibet Plateau still wore its winter coat. From Xining to Golmud, remnants of snow could still be seen lying among the yellow grasses.

　　The Guanjiao Tunnel, the longest tunnel on the plateau railway, averages over 3,600 meters in elevation, where the cold and oxygen scarcity make it a critical choke point of the Qinghai-Tibet Railway. It was once known as a "devil section" in world railway history, where trains had to creep at 15 km/h.

　　Today, the old Guanjiao Tunnel and the balloon-shaped looping track that helped trains overcome elevation differences still remain, flanked by near-vertical cliffs that are awe-inspiring. In 2014, the new Guanjiao Tunnel was fully completed, reducing the time for trains to cross Guanjiao Mountain from two hours to just over ten minutes. What was once an impassable barrier has been transformed into a smooth passage.