Aerial photo taken on Nov. 9, 2020 shows the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)

Builders work at the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province, Nov. 9, 2020. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)

A builder works at the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province, Nov. 9, 2020. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)

A builder works at the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province, Nov. 9, 2020. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)

Aerial photo taken on Nov. 9, 2020 shows the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)

Builders work at the construction site of the Longzhen train depot of Guangzhou Metro Line 18 in Guangzhou, south China's Guangdong Province, Nov. 9, 2020. Shaped like a guitar, the Longzhen train depot takes up an area of 210,000 square meters. When it is finished, the facility will function as a maintenance center for trains of Guangzhou Metro Line 18, a subway line which is also under construction with a maximum designed speed of 160 kilometers per hour. (Xinhua/Liu Dawei)