New trains run across rocky mountains and the Great Wall to the north of Beijing like bullets（子弹）. They run on a high-speed railway line between Beijing and Zhangjiakou. The opening was on Dec 30, 2019.
The railway is an important support project for the 2022 Winter Olympics. The 174-km railway's trains move at a top speed of 350 km/h. This reduces the travel time between Beijing and Zhangjiakou, the Winter Games will be held there, from over three hours to only 47 minutes. It has 10 stops in total. It will help improve tourism. There are places of interest nearby.
Some of the trains on this railway are smart trains that can run by themselves. With the help of the Beidou Navigation Satellite System, they can automatically（自动）start, run between stations, change their timing according to the time table, correctly stop at a station, and open and close their doors. Passengers can also watch live sports programmes during the Winter Olympics on the train, which is helped with 5G technology.
Some people consider Zhan Tianyou as "the father of China's railways". Who is Zhan Tianyou? In 1872, the Qing government chose 30 young boys to be sent to the US to study. They were the first students in Chinese history to study abroad. Zhan Tianyou was one of them. After graduating from Yale University, Zhan came back to China. In 1905, the Qing government decided to build a railroad between Beijng and Zhangjiakou. Zhan, who studied engineering, led the project. The project is best-known for its Y-shaped switchback（人字形坡路）. There are many mountains along the Beijng-Zhangjiakou railway. It was difficult for trains to climb the mountains.
He led construction（建设）on the old Beijing—Zhangjiakou railway, China's first independently—designed railway. It was not possible to build a railway without foreign help at that time. But Zhan, the head engineer of the railway project, insisted（坚持） that it could be done. Zhan came up with an idea to reduce the slope（坡度）: a Y-shaped switchback. Instead of going directly from A to B along a steep（陡的）slope, the train goes from A to C first and then from C to B. This makes the slope much less steep.
After many difficulties, the Beijing—Zhangjiakou line went into operation in 1909. Its trains ran at 35 km/h.
As President Xi Jinping said, the Beijing-Zhangjiakou railway stands for the development of China's railways over more than a century, as well as China's development in general.
