(HOU DEQIANG)

A freight train speeds past the Kunlun Mountains on the Qinghai-Tibet Railway in northwest China's Qinghai Province on July 9.

In the seven years since its operation, the Qinghai-Tibet Railway, the longest and highest railway in the world, has carried nearly 64 million passengers and 300 million tons of goods.

Meanwhile, several new railway lines are either under construction or being planned to form a rail network on the sparsely populated Qinghai-Tibet Plateau.