Sound level reduced to 50 decibels, similar to that of normal conversation

Engineers and technicians working on the Shenzhen-Maoming Railway, an important transport link between the two coastal cities in Guangdong province, have finished construction of a fully enclosed noise barrier on a section running through an ecological scenic site.

The 2,036-meter arched steel structure, with sound insulation and concrete acoustic boards, is just 800 meters from Birds' Paradise, a scenic and ecological attraction in Jiangmen, Guangdong.

The attraction, which is covered by 400-year-old banyan trees, is home to more than 30,000 birds of over 40 varieties.

The paradise became a popular site after celebrated Chinese writer Ba Jin penned The Birds' Paradise after he took in the lush scenery of the tree-covered island in the early 1930s.

The noise barrier cost 180 million yuan ($27.5 million), according to Fifth Construction Ltd of China Tiesiju Civil Engineering Group.

It was the first of its kind in high-speed railway construction using technology for a fully enclosed sound barrier, it said.

Construction was not allowed between March and July, which is often a breeding period for birds on the island, the builder said.

"The fully enclosed sound barrier will help reduce about 30 percent of traffic noise, a safe standard for the living and breeding environment of the birds," said Mo Yongchun, a manager with China Tiesiju Civil Engineering Group.

The 390-kilometer Shenzhen-Maoming Railway, which is designed for train speeds up to 200 kilometers per hour, is scheduled to open in mid-2018.

According to Mo, the noise will be 76.5 decibels at a distance of 3.5 meters from the railway when a train passes - about the same as a car.

"It will be below 50 decibels at the Birds' Paradise," said Liu Zhenbiao, assistant chief engineer of the Bridge Design and Research Department of the China Railway Siyuan Survey and Design Group. That is about as loud as a normal conversation.

"The noise will pose no threat to the living conditions of birds," he said.

According to Liu, the barrier is designed to stand up to the high winds of a typhoon.

qiuquanlin@chinadaily.com.cn