Visitors look around in a CETROVO 1.0 subway car in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)

A visitor takes photos of a CETROVO 1.0 subway car in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)

A CETROVO 1.0 subway car is on display in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)

A visitor takes a look inside the cockpit of a CETROVO 1.0 subway car in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)

A CETROVO 1.0 subway car is on display in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)

Visitors board a CETROVO 1.0 subway car in Qingdao, east China's Shandong Province, June 26, 2024. The CETROVO 1.0 subway car was launched in Qingdao on Wednesday. With a carbon fiber composite body and frame, it is lighter and more energy-efficient than the traditional subway train. (Xinhua/Li Ziheng)