Why did the trains in Tianjin and Beijing stop?

Trains in Tianjin and Beijing were stopped because of the Tianjin epidemic. According to the official customer service information of 12306, the railway department suspended the sale of tickets from Tianjin South Station, Junliang North Station, Binhai Station, Tianjin North Station, Binhai West Station, Binhai North Station, Tanggu Station, Lutai Station, Baodi Station, Jizhou North Station, Yangliuqing Station, Jinghai Station, Yangcun Station, Jizhou Station and Wuqing Station to Beijing Station. According to the requirements of epidemic prevention in Tianjin, all personnel entering and leaving Tianjin must hold negative nucleic acid test certificate within 48 hours. Bayonets or special passages should be set up in railways, passenger stations and high-speed intersections, and Tianjin personnel leaving Beijing should verify the negative certificate of nucleic acid test and the green code of health code within 48 hours. Persons with fever and abnormal health code should fulfill their personal protection responsibilities, actively cooperate with health monitoring and nucleic acid detection, and do not leave Tianjin or enter Beijing before eliminating the risk of infection.