Chinese bullet trains had to be given a shower after photos of high-speed trains, filthy after travelling through smog-stricken areas, caught the attention of netizens this week. 

The normally sleek trains were caught on camera looking less than their usual shiny selves when they arrived at their destinations, having passed through smog-clogged eastern and northern parts of China.

But no worries, the trains have now been cleaned up, as photos on the official peoplerail.com website show. 

Just like we have our cars washed, an automatic “trainwash” system has been set up in Shanghai. When the infrared rays sense a train, the system starts sprinkling recycled water at the carriages. A cleaning liquid is then applied to the whole train as soft moving brushes wipe the dirt out of every crevice. Finally, a chemical mixture of resin, salt and coal is sprayed on to remove any grime still firmly stuck to the train.

This was not enough this time, however. Faced with hard to remove smog dirt, workers also had to use a two-meter-long brush and detergent to clean the head at least four times. According to the Shanghai Industry and Trade Company of Trains, which operates the “trainwash,” four workers were needed to wash one head, with each worker having to brush up and down the side more than 1,600 times.

“The first and last cars of each train have more dirt so they took at least 20 minutes to wash. Inexperienced workers would feel their arms ache,” Yao Jianmin, a manager at the company said. Washing one train took about 45 minutes, he added. 

Since New Year’s Eve, nearly 50 cities in northern China have been blanketed with heavy smog. Beijing has issued an orange alert for the heavy smog, indicating it will last until Saturday.