京山线北京～天津间是全国铁路运输最繁忙的干线区段之一。1984年运行旅客列车34对,货物列车80多对。重车方向货流密度达六千多万吨,能力利用率已达107％。由于运输能力已经饱和,为了提高输送能力,采取了旅客快车与直达货物列车等速运行的措施,1982年有16对旅客快车按平行图运行,使旅客快车运行时间由五十年代的一小时三十分延长为两小时十分,个别达到 Jingshan Line Beijing to Tianjin is one of the busiest trunk sections in China. In 1984, there were 34 pairs of passenger trains and more than 80 pairs of freight trains. Heavy cargo flow direction of more than 60 million tons, capacity utilization has reached 107%. Due to the saturation of transport capacity, in order to improve the transport capacity, measures were taken to provide constant speed passenger trains and direct freight trains. In 1982, 16 pairs of passenger express trains operated in a parallel map, enabling passengers to operate in express trains from one hour to three in the 1950s Very extended to two hours very, individually achieved