CHONGQING - High-speed trains linking northwest China's Xi'an and southwest China's Chongqing, will begin operation on Wednesday, slashing the travel time between the two cities from 9.5 hours to just 5.5.

The new route includes a new section of the high-speed rail line linking Xi'an, capital of Shaanxi Province with Chengdu, capital of Sichuan Province, which is also set to start operation on Wednesday.

The 643-km Xi'an-Chengdu line is China's first rail route to run through the Qinling Mountains, which are the natural boundary between north and south China.

With a designed speed of 250 kph, it will slash the travel time between Xi'an and Chengdu from about 7 hours to about 4.