Strange Friends (1982)

Three strangers, two men and a woman, end up sharing a compartment on a train leaving Beijing for Shanghai -- the lone woman is quiet while one of the young men is gregarious and funny, and the other is more reserved, but compassionate. Eventually, the men cannot help but note the woman's silence -- it turns out she is running away from her employers who felt she was pretty much a derelict, and from some friends who were of questionable ethics, though she is not about to say anything to the two men. When she gets off the train in Nanjing, one of the young men from the train -- somewhat worried about his silent travel partner -- decides to follow her to make sure she will be okay. And it is a good thing he did so because she is menacingly approached by some obvious thugs and the young man gets her out of the potentially hazardous encounter.