Guangzhou Metro Group and CRRC Zhuzhou Locomotive Co Ltd jointly unveil their latest green intelligent urban rail vehicles in Guangzhou, capital of Guangdong province, on Monday. [Photo provided to chinadaily.com.cn]

Some compartments in the trains are fitted with electric folding seats. Folding the seats during peak travel times can increase passenger capacity.

The vehicles will be used on the city's metro line 12, which is currently under construction, according to Gao.