中文摘要：

在综述灵活性理论和国内外学者相关研究的基础上，结合路网系统运输能力理论体系及铁路网的特性，提出铁路路网系统运输能力灵活性定义，分析它与路网系统运输能力可靠性的区别和联系，并与国外类似概念进行了比较。分析表明，本文提出的铁路路网系统运输能力灵活性定义更符合我国铁路网系统实际。从深入研究路网系统潜在运输能力出发，给出了路网系统运输能力灵活性的量化公式，并分析两种路网系统运输能力灵活性的对立同一性，以它来描述路网拓扑结构的演变。通过实际算例表明，本文提出的定义与计算方法，可为铁路路网规划和建设提供有效的客观量化依据。

英文摘要：

Starting from the potential carrying capacity of railway network theories, the definition and calculating formula of railway network carrying capacity flexibility is given on the basis of flexibility theories and relative study at home and abroad. The difference and relationship between carrying capacity flexibility and reliability of the railway network are analyzed. The real calculating instance shows that the railway administration can know clearly about topological structure evolvement of the railway network, and make out more reasonable planning and constructing schemes.