Chinese news site iFeng shows numerous screens and display read, "Wang Peng ni mei" (王鹏你妹) or as ShanghaiIst explains: it's literally "Wang Peng, your sister", but that means something like, "Wang Peng, fuck you" in English. (It can also mean a slightly more lighthearted "Wang Peng, fuck off").
No wonder station employees scrambled to cover up the messages.
What isn't clear is why the monitor system was displaying this message. Did someone hack the system? Is this a disgruntled worker? Who is Wang Peng?
北京地铁电视屏显示"王鹏你妹" 官方致歉(组图) [iFeng]