A subway train enters the automatic cleaner in Xiamen, Fujian province. [Photo/sunnews.cn]

Subway trains in Xiamen, eastern Fujian province get a thorough cleaning eight times a month, providing passengers with a comfortable and clean environment to ride in, said local media.

Cleaning staff clean the inside of the carriages daily. The windows, seats, floor, even the hand pull-rings, have to be cleaned one by one.

In addition, the exterior of each subway train is washed eight times a month. To avoid interfering with daily operations, the cleaning usually takes place late at night.

The automatic cleaner in the subway train garage in Xiamen only needs one operator. [Photo/sunnews.cn]

Although the subway train has six carriages, each of which is 19 meters long, the cleaning process is not as complex as one might think. The entire process is automated and takes just five minutes to complete.

It is estimated that about 0.4 tons of water are used to wash each train, but 80 percent of it is recycled.