
A technician operates an unmanned submersible for checking piers of a bridge of Chengdu-Guiyang High-Speed Railway in Guiyang, southwest China's Guizhou Province, Feb. 19, 2024. Many high-tech products including unmanned submersibles have been applied to ensure smooth operation of railway lines during this year's Spring Festival travel rush which started on Jan. 26. (Xinhua/Liu Xu)

Technicians operate an unmanned submersible for checking piers of a bridge of Chengdu-Guiyang High-Speed Railway in Guiyang, southwest China's Guizhou Province, Feb. 19, 2024. Many high-tech products including unmanned submersibles have been applied to ensure smooth operation of railway lines during this year's Spring Festival travel rush which started on Jan. 26. (Xinhua/Liu Xu)

Technicians prepare unmanned submersibles for checking piers of a bridge of Chengdu-Guiyang High-Speed Railway in Guiyang, southwest China's Guizhou Province, Feb. 19, 2024. Many high-tech products including unmanned submersibles have been applied to ensure smooth operation of railway lines during this year's Spring Festival travel rush which started on Jan. 26. (Xinhua/Liu Xu)

Technicians operate an unmanned submersible for checking piers of a bridge of Chengdu-Guiyang High-Speed Railway in Guiyang, southwest China's Guizhou Province, Feb. 19, 2024. Many high-tech products including unmanned submersibles have been applied to ensure smooth operation of railway lines during this year's Spring Festival travel rush which started on Jan. 26. (Xinhua/Liu Xu)