Tunnel section of high-speed railway in Guangdong Province under construction

A high-speed railway connecting Shenzhen city and Jiangmen city, in south China's Guangdong Province, recently started construction. Up to 98 percent of the line will be bridges and tunnels, according to the China State Railway Group Co., Ltd.

A representation features the shield tunneling machine working under the sea. (Photo/China Railway)

A 13.69-km tunnel at the mouth of the Pearl River, which will be as deep as 115 meters below the sea level, will be a key project during the construction of the line. It is also the deepest undersea tunnel in the country.

The route of the high-speed railway. (Photo/China Railway)

Two domestically built shield tunneling machines have been tailored for the tunnel excavation.

Photo shows a shield tunneling machine used to excavate the tunnel. (Photo/China Railway)

Photo shows a shield tunneling machine used to excavate the tunnel. (Photo/China Railway)

According to Yang Cen, the first female shield tunneling machine operator in the country, as the soil condition under the sea varies, the shield tunneling machine can easily deviate from the designed route during excavation, and in this case, a driver is needed to control the direction in which the machine moves.

"The operator control room of the machine is about 15 square meters and there are more than 200 buttons and nine screens inside the room for me to operate the machine. I'm very proud to be able to operate such a complex machine at more than 100 meters below sea level," Yang expressed.

Photo shows a shield tunneling machine used to excavate the tunnel. (Photo/China Railway)

To be completed in five and a half years, the 116-km high-speed railway is an important part of the high-speed railway network in China's coastal areas.

Photo shows the tunnel at the mouth of the Pearl River. (Photo/China Railway)