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.     

可编程逻辑控制器在轨道交通隧道通风监控系统中的应用

以达万铁路隧道通风监控系统为例,介绍了可编程逻辑控制器(PLC)在铁路隧道通风监控系统中的应用,进而可推广于城市轨道交通.从硬件设计到软件组态,本系统采用西门子PLC系列产品,实现从本地监控的数据采集到远程监控的自动控制.运行结果显示,系统具有很好的可靠性和稳定性.     

基于遗传算法的单线列车运行调整体系

针对单线列车运行的特点，提出了“相邻列车”的概念，根据此概念建立了单线列车运行调整模型，并推导了列车运行图偏差函数作为模型调整目标．鉴于列车运行调整问题的解空间太大，用一般的运筹学方法难以有效地求解，提出了基于遗传算法的优化求解算法．该算法根据被调整列车的等级将原问题分解成若干子问题，并在对每个子问题求解的过程中，运用遗传算法在解空间中寻优．仿真结果显示了该模型和算法在应用于实际运行调整时的有效性和实时性．