本文以京哈干线长春工务段管辖的434km既有线提速为例，对制约既有线提速的主要因素曲线和道岔等线路条件进行了重点剖析和论述，并科学合理地提出了改造方案。同时，在提速后的轨道强化上，以及管理和提高线路维修水平上，都采取了切实可行的有效措施。

This paper analyses and describes the technical conditions and main factors of restricting speed rising on existing line, such as track curve and switch point, presents reconstruction scheme for the problem mentioned above based on an example of speed rising on existing line of 435 km on Beijing-Haerbin Railway Line, and proposes that the effective measures should be adopted for improving management and maintenance level of track after speed rising.