Drone carries first cable across record-breaking bridge in 10 minutes

[Video/Yongpai app]

A heavy-lift drone carried a 1,700-meter-long pilot rope across the Xihoumen waterway on Sept 16, marking a key step in building the Xihoumen Highway and Railway Bridge.

The drone took off from one of the bridge's main towers with the 2.5-millimeter-diameter rope and crossed about 1,500 meters of open water in just 10 minutes before reaching the other tower.

The pilot rope will pull progressively thicker ropes across the channel, eventually preparing the way for the catwalks and main suspension cables. Catwalks serve as temporary aerial work platforms beneath the main cables during suspension bridge construction.

Engineers chose a drone because the Xihoumen waterway is known for strong winds, rough seas, and heavy shipping traffic. Compared with helicopters or vessels, the drone required less preparation and allowed the crossing to be completed quickly, reducing disruption to marine traffic.

The 3,118-meter Xihoumen bridge will have a 1,488-meter main span and carry both road and rail traffic between Jintang and Cezi islands. It is part of the 76.4-kilometer Ningbo-Zhoushan Railway, which is scheduled to open in 2028. Once completed, the railway is expected to cut the journey between Ningbo and Zhoushan to 26 minutes.