Delay Restoration of Single-Track Railway Rescheduling

On the basis of analysis of the principle of delay restoration in a disturbed schedule, a heuristic algorithm for rescheduling trains is developed by restoring the total delay of the disturbed schedule. A discrete event topologic model is derived from the original undisturbed train diagram and a back propagation analysis method is used to label the maximum buffer time of each point in the model. In order to analyze the principle of delay restoration, the concept of critical delay is developed from the labeled maximum buffer time. The critical delay is the critical point of successful delay restoration. All the disturbed trains are classified into the strong-delayed trains and the weak-delayed trains by the criterion of the critical delay. Only the latter, in which actual delay is less than its critical delay, can be adjusted to a normal running state during time horizon considered. The heuristic algorithm is used to restore all the disturbed trains according to their critical details. The cores of the algorithm are the iterative repair technique and two repair methods for the two kinds of trains. The algorithm searches iteratively the space of possible conflicts caused by disturbed trains using an earfiest-delay-first heuristics and always attempts to repair the earliest constraint violation. The algorithm adjusts the weak-delayed trains directly back to the normal running state using the buffer time of the original train diagram. For the strong-delayed trains,the algorithm uses an utility function with some weighted attributes to determine the dynamic priority of the trains, and resolves the conflict according to the calculated dynamic priority. In the end, the experimental results show that the algorithm produces ＂good enough＂ schedules effectively and efficiently in disturbed situations.     

意大利国铁采用的路基修复新方法

意大利国铁最近已开始实施一项创新方案，旨在修复、改善由高速、重载引起，已出现不稳定迹象的既有轨道路堤(约1200km)。     

内燃机车柴油机曲轴修复方法

内燃机车柴油机在长时间使用后其曲轴的修复，也即内燃机车柴油机使用寿命的恢复，是一个众所周知的实际问题。内燃机车修理厂在执行交通部有关节约资源和进口产品另产化的任务时，这一问题就更为突出。但是在许多修理厂中，由于曲轴修复比较和修理成本较高，所以未能进行这项工作。曲轴修复的主要方法有；矫正法－－消除振摆；研磨法－－消除曲轴的椭圆度和局部表面机械损伤，如擦伤、划痕；镀复法－－修复被磨损之轴颈的直径；堵焊     

锰对体内必需元素生物转运的影响

动物实验发现，锰可促进或妨碍某些必需元素如Ｚｎ、Ｃｕ、Ｆｅ、Ｃｏ和Ｃａ等的吸收、分布与排泄。职业人群调查也观察到锰对血液、头发和精液必需元素的影响。临床研究表明，锰对Ｍｇ、Ｃａ、Ｚｎ和Ｆｅ的影响与中毒的临床表现有关。揭示锰对体内必需元素的生物转运过程有干扰作用。     

铁路辙叉的现场修复技术

介绍高锰钢及高碳钢辙叉的现场修复工艺及其专用焊机的研制，分析辙叉现场修复的技术经济效益。