People work at the construction site of a subway station of Guangzhou Subway Line 18 in Guangzhou, south China's Guangdong Province, April 23, 2020. The construction of Guangzhou Subway Line 18 has been resumed. The maximum designed speed of the line is 160 kph. (Photos: Xinhua)

People work at the construction site of a subway station of Guangzhou Subway Line 18 in Guangzhou, south China's Guangdong Province, April 23, 2020. The construction of Guangzhou Subway Line 18 has been resumed. The maximum designed speed of the line is 160 kph.

People work at the construction site of Guangzhou Subway Line 18 in Guangzhou, south China's Guangdong Province, April 23, 2020. The construction of Guangzhou Subway Line 18 has been resumed. The maximum designed speed of the line is 160 kph.

Aerial photo taken on April 23, 2020 shows the construction site of a subway station of Guangzhou Subway Line 18 in Guangzhou, south China's Guangdong Province. The construction of Guangzhou Subway Line 18 has been resumed. The maximum designed speed of the line is 160 kph.

People work at the construction site of a subway station of Guangzhou Subway Line 18 in Guangzhou, south China's Guangdong Province, April 23, 2020. The construction of Guangzhou Subway Line 18 has been resumed. The maximum designed speed of the line is 160 kph.