“七五”期间我国铁路建设的方针“以归线改造为主,适当修建急需新线”。在既有线改造和增建第二线工程中都要遇到过渡工程的问题。大型区段站或编组站,由于既有线的线路、桥梁、隧道、地形、地势及车站位置、城市规划等各种因素的影响,确定站场需在原有站场的基础上进行改建或扩建,新的站场不能一次建成,而必须分步修建,这就形成了分步过渡。既使在比较小的中间站,改建或扩建均存 During the “Seventh Five-Year” period, the guideline of railway construction in our country is to “rejuvenate the main line and properly build a line urgently needed”. In the existing line reconstruction and construction of second-line projects have to meet the transition project. Due to the influence of various factors such as the existing lines, bridges, tunnels, topography, terrain and station locations, urban planning and other factors, the station or marshalling station at a large scale shall determine that the station yard needs to be rebuilt or expanded on the basis of the original station yard, The new station can not be built once, but must be built step by step, which formed a step by step transition. Even in the smaller intermediate stations, reconstruction or expansion of both