The Xiangyang East to Badong section of the Zhengzhou-Chongqing high-speed railway officially entered trial operation recently, marking the countdown to the opening of the whole line.

The railway that connects Zhengzhou of Henan province and Southwest China's Chongqing municipality is 1,063 kilometers long with designed speeds from 250 km per hour to 350 km/h.

It consists of the Zhengzhou-Wanzhou section and Wanzhou-Chongqing section.

The Zhengzhou-Wanzhou section is 818 km long with a designed speed of 350 km/h, and the Wanzhou-Chongqing section is 245 km long with a designed speed of 250 km/h.

Central Henan province, the Chengdu-Chongqing economic circle and the Yangtze River Economic Belt will be more closely connected once the whole line is opened, according to a news conference held by China Railway Chengdu Group in Chongqing on May 17.

"The line is very rich in tourism resources and has low demand for freight trains, and so is very suitable for a high-speed railway passenger line," said Xiao Qiang, deputy design director of the project.

He said to maximize the transportation quality and efficiency, the evaluation took six years. The project was confirmed in 2015.

The Chongqing section of the Zhengzhou-Chongqing high-speed railway has the highest ratio of bridges and tunnels in China－making up 98 percent of the line.

Liu Baolin, the project's chief tunnel expert, said that there existed many hidden dangers drilling in complicated geological conditions, such as in the Karst region, and there were multiple factors to think about, such as disaster prevention and rescue, and tunnel drainage.

"The design is difficult, with geological conditions such as landslides and rockfalls," said Lei Min, the project's chief bridge expert.

"There are a total of 32 bridges in the Chongqing section."