Why isn’t the Lanzhou-Xinjiang High-Speed ​​Railway built parallel to the Lanzhou-Xinjiang Railway?

Lanzhou-Xinjiang High-speed Railway is a major artery in Northwest my country and the most convenient and fastest travel route in Northwest China. The construction of Lanzhou-Xinjiang High-speed Railway started in November 2009 and was completed and put into operation in December 2014. It is the world's longest high-speed railway built and opened to traffic at one time. Its completion has greatly improved the railway transportation capacity between China and Central Asia, Europe and other places, marking the entry of Xinjiang and Qinghai into the "high-speed railway era".

If you observe the Lanzhou-Xinjiang High-speed Railway, you will find that the Lanzhou-Xinjiang High-speed Railway is not built parallel to the Lanzhou-Xinjiang Railway. The Lanzhou-Xinjiang High-speed Railway makes a big turn to the south. The Lanzhou-Xinjiang Railway does not pass through Xining on the Qinghai-Tibet Plateau, but the Lanzhou-Xinjiang High-speed Railway does. Moreover, the Lanzhou-Xinjiang High-speed Railway does not take the relatively flat Hexi Corridor, but passes through many mountains and plateaus.

First of all, the functions of the Lanzhou-Xinjiang High-speed Railway and the Lanzhou-Xinjiang Railway are different, because there are already railways where the Lanzhou-Xinjiang Railway passes, and there is no need for high-speed railways at all. Moreover, most of the places where the Lanzhou-Xinjiang Railway passes are small cities along the line, while the high-speed railway serves more large cities.

The Lanzhou-Xinjiang high-speed railway has to go through Xining on the Qinghai-Tibet Plateau, and Xining is also the largest city on the Qinghai-Tibet Plateau. The Lanzhou-Xinjiang high-speed railway will have a larger passenger flow in Xining, so the Lanzhou-Xinjiang high-speed railway must go through Xining.