Guiyang-Nanning high-speed railway under construction

A technician uses a flaw detector to detect rail track near the Duyun East Railway Station along Guiyang-Nanning high-speed railway in Duyun, southwest China's Guizhou Province, Feb. 27, 2023. The Guiyang-Nanning high-speed railway, with a maximum speed of 350 km per hour, is expected to go into service in 2023. (Xinhua/Liu Xu)

A technician uses a filler gauge to monitor the rail track switch gap near the Duyun East Railway Station along Guiyang-Nanning high-speed railway in Duyun, southwest China's Guizhou Province, Feb. 27, 2023. The Guiyang-Nanning high-speed railway, with a maximum speed of 350 km per hour, is expected to go into service in 2023. (Xinhua/Liu Xu)

This aerial photo taken on Feb. 27, 2023 shows technicians conducting fine adjustment work of rail tracks near the Duyun East Railway Station along Guiyang-Nanning high-speed railway in Duyun, southwest China's Guizhou Province. The Guiyang-Nanning high-speed railway, with a maximum speed of 350 km per hour, is expected to go into service in 2023. (Xinhua/Liu Xu)

Technicians use a gauging apparatus to check the rail track near the Duyun East Railway Station along Guiyang-Nanning high-speed railway in Duyun, southwest China's Guizhou Province, Feb. 27, 2023. The Guiyang-Nanning high-speed railway, with a maximum speed of 350 km per hour, is expected to go into service in 2023. (Xinhua/Liu Xu)

Working staff conduct rail track grinding work along rails near the Duyun East Railway Station along Guiyang-Nanning high-speed railway in Duyun, southwest China's Guizhou Province, Feb. 27, 2023. The Guiyang-Nanning high-speed railway, with a maximum speed of 350 km per hour, is expected to go into service in 2023. (Xinhua/Liu Xu)