Liangshan is the Yi Autonomous Prefecture located in Sichuan Province.
They are sitting in a train car making announcements. The man is of the Yi Nationality. The insignia on his teacup is the railroad insignia like this pin.
The Yi people are the 6th largest minority of China. Below is music of the Yi minority.
A Papercut of Mao Zedong from the Cultural Revolution period.
Changbai refers to 长白山 the Changbai Mountains located in the Northeastern province of Jiling 吉林 near the North Korean border.
It it the Chinese railway insignia. You can also see it in this painting on the man’s teacup.