一、问题的提出京广线全长2300多公里,是我国南北交通命脉之一。目前这条大干线一些区段的通过能力利用率达到80%以上,有些区段达到90～100%。郑州——武昌间,预计一些区段南下的货运量,近期将增加到4000万吨左右,远期增加到5000万吨左右。华南、华中地区的鲜活易腐货物运量的增长,湖北磷矿资源的开发,也迫 First, the question raised Beijing-Guangzhou line total length of more than 2,300 kilometers, is one of the lifeblood of North-South traffic. At present, the capacity utilization rate of some sections of this major trunk line has reached more than 80%, with some sectors reaching 90-100%. Between Zhengzhou and Wuchang, it is estimated that the cargo volume south of some sections will increase to 40 million tons in the near future and will increase to about 50 million tons in the future. In southern China, Central China, the growth of fresh perishable cargo traffic, Hubei phosphate rock resources development, but also forced