Air conditioning is indispensable for train travelers in summer. However, for China’s high-speed train, its maintenance is not easy. /VCG Photo

When a train achieves a certain mileage, the air-conditioning units will suck some sundries into the heat sinks, affecting the cooling effect. /VCG Photo

Cleaning staff from northwestern China’s Xi’an Railway Bureau have to wash more than 500 units manually each day at high temperatures, to ensure the normal functioning of the equipment. /VCG Photo

Workers in protective suits use high-pressure water guns and special long-handle brushes and they have to endure hot air generated by the power supply. /VCG Photo