A tunnel boring machine emerged from a depth of 66 meters underground at the Sanshan shaft in Guangzhou, the capital of Guangdong province, on Tuesday morning, marking the completion of the first section of the first ultra-large diameter high-speed rail tunnel in the city's central urban area.

The 13.2-kilometer Xilang tunnel is a critical control project for the entire link connecting the Guangzhou Railway Station to Guangzhou South Railway Station, which spans a total length of 16 kilometers.

The link, with a designed speed of 200 kilometers per hour, is an important part of an initiative of the Guangzhou railway hub, allowing high-speed railways to enter into the urban center of the city.

The Xilang tunnel has the smallest turning radius among large shield railway tunnels in the Guangdong-Hong Kong-Macao Greater Bay Area, with complex geological conditions, high construction difficulty, and significant safety risks.

Construction of the tunnel involves three large-diameter tunnel boring machines working in three sections. As of Tuesday, 8,382 meters of the tunnel have been excavated, accounting for 71 percent of the total shield tunneling work.

Once the project is completed, it will connect key railway hubs such as Guangzhou Railway Station, Guangzhou Baiyun Railway Station, and Guangzhou South Railway Station, according to Liu Defeng, chief engineer from the link's construction command office of the Guangzhou Engineering Construction Command of the China Railway Guangzhou Group.

"It will significantly enhance the inter-connectivity of rail transportation within the Greater Bay Area, as high-speed trains from Shenzhen, Hong Kong, Zhuhai, and Macao will be able to reach the central urban area of Guangzhou directly," Liu said.

After completion of the link, the travel time from Guangzhou South Railway Station to the city center will be reduced from 40 minutes to approximately 15 minutes, according to Liu.