The first high-speed railway through the Qinling Mountains - a habitat for rare wildlife, including the giant panda - will seek harmony between man and nature, according to those behind the project.

At 643 kilometers, the line will link Xi'an, Shaanxi province, with Chengdu, Sichuan province. It will pass through the Qinling Mountains, which contain seven national natural reserves and 21 provincial level natural reserves, according to Lai Wenhong, deputy director of China Railway First Survey and Design Institute Group.

When the line becomes operational at the end of this year, train speeds are expected to reach 250 kilometers per hour, cutting travel time between Chengdu and Xi'an from 13 hours to less than three.

The line will go through two areas related to rare wild animals - the Tianhua Mountain Natural Reserve Area (giant panda habitat) and Yangxian county (crested ibis habitat). To minimize human influence on nature, especially the wild animals, years of research and trials were carried out.

The Qinling Mountains are home to China's largest wild giant panda population, with about 345 of the animals living there, according to China's Fourth National Survey on Giant Pandas, which was conducted two years ago.

To avoid disturbing the pandas, the railway was designed either to go around the panda's major activity region or run through tunnels within the Tianhua Mountain area, according to Lai.

"Protective shields will be placed near the entrance of each tunnel to prevent animals from going in," he said.

Twenty tunnels are designed for the 134-kilometer Qinling Mountains stretch. Most are 800 to 1,000 meters underground, according to Xi'an-Chengdu High-Speed Railway Shanxi Co, which is building the tracks in Shaanxi province.

The more numerous and deeper the tunnels, the greater are the challenges faced by the construction team. According to the company, geologic structures are more complicated in deeper areas, where hard rock may easily burst and soft rocks are more likely to be deformed during construction.

However, tunnels minimize disturbances, which not only protects the pandas but other rare animals in the region as well, including golden snubnosed monkeys and the Qinling takin, species whose total population in Qinling is no more than 5,000 each.

A rare bird - the crested ibis, which is widely believed to bring luck in China - is well protected, Lai said. The line travels less than 1 km through the region where crested ibises sometimes fly. But protective nets will be built along 17 kilometers of track to prevent any damage to the birds, he said.

"We invited experts from China and Holland and learned from bird protection projects overseas. Plenty of different shapes of nets with various materials were tested before we made a final choice," he said.

"The diameter of the mesh was adjusted many times to make sure that the ibises will not fly into a train or get their beaks stuck."

The 4-meter-high nets on both sides will cost nearly 50 million yuan ($7.35 million). No crested ibises were hurt by the nets during a trial.

yangwanli@chinadaily.com.cn