A sign printed on the platform of a Beijing subway Line 6 station indicates different temperature sections on the train. /VCG Photo

Responding to passenger complaints about the AC temperature on the train, Beijing Line 6 has started to offer different temperature settings in each subway car. /VCG Photo

The first four cars are set to a high-cool mode, while the remaining four are on the low-cool mode. /VCG Photo

Passengers are happy with the more personalized service. /VCG Photo