Dispatching and coordination in multi-area railway traffic management

This paper deals with the development of decision support systems for traffic management of large and busy railway networks in case of severe disturbances. Railway operators typically structure the control of complicated networks into the coordinated control of several local dispatching areas. A dispatcher takes rescheduling decisions on the trains running on its local area while a coordinator addresses global issues that may arise between areas. While several advanced train dispatching models and algorithms have been proposed to support the dispatchers' task, the coordination problem did not receive much attention in the literature on train scheduling. This paper presents new heuristic algorithms for both local dispatching and coordination and compares centralized and distributed procedures to support the task of dispatchers and coordinators. We adopt dispatching procedures driven by optimization algorithms and based on local or global information and decisions. Computational experiments on a Dutch railway network, actually controlled by ten dispatchers, assess the performance of the centralized and distributed procedures. Various traffic disturbances, including entrance delays and blocked tracks, are analyzed on various time horizons of traffic prediction. Results show that the new heuristics clearly improve the global performance of the network with respect to the state of the art.     

An agent-based support system for railway station dispatching

For those railway stations without being automated, railway traffic dispatching still depends on dispatchers, especially under disturbed circumstances. In this study, an agent-based support system, named D-Agent, is developed to assist human dispatchers to make decisions in station operation. To this end, the common knowledge and possible difficulties concerning a station dispatcher in his/her routine work are firstly studied, and the D-Agent is proposed with the purpose of working out practicable solutions to these challenging tasks as a dispatcher does. Then the general model of the D-Agent is established, containing five basic modules: local database, knowledge base, skill base, reasoning mechanism and communication interfaces. The internal skills of the D-Agent are designed to execute various tasks in different scenarios. Besides, a skill extension of the D-Agent with mathematical formulations is particularly discussed in this paper, to find feasible and optimal traffic control solutions in disturbance situations such as train delays and route conflicts. The D-Agent is designed to learn from its own experimental history in applying different skills, and evaluate the skills by preference weights of alternative solutions in a particular task. This procedure allows the agent to have potential for continuous improvement. To verify the applicability of the proposed support system, a D-Agent for a terminal station of subway is simulated. The numerical example of train delays and route conflicts shows that the D-Agent can generally perform as a station dispatcher in fulfilling the specific tasks, estimate the traffic state in different operation strategies and support the decision-making of favored solutions. Significantly, it indicates that the mathematical methods can also been employed by an intelligent agent.     

Development of an expert system for optimizing natural gas pipeline operations

This paper presents an expert system as a decision support tool to optimize natural gas pipeline operations. A natural gas pipeline control system is a controlling system that involves many complicated operating processes. Since a dispatcher (who operates the system) might not be able to handle all of his or her tasks consistently, an expert system has been developed for optimizing the operations by providing consistent, fast and reliable decision support to the dispatcher. Consequently, inconsistency in the dispatcher's performance can be minimized. To build an expert system, the knowledge from an experienced dispatcher, who is familiar with the process in this controlling system is acquired and that knowledge has been implemented as rules in the knowledge base of the expert system. When this expert system has been validated by gas pipeline experts, it can help inexperienced dispatchers to operate the processes more effectively. The expert system is implemented on the real-time expert system shell G2 (trademark of Gensym Corp. of USA). The system also consists of a user interface that helps dispatchers visualize system conditions.     

铁路无线列调系统的功能运用分析

列车无线调度通信系统,简称无线列调,是铁路无线通信的主要组成部分,是组织铁路运输、保障行车安全、提高生产效率的重要通信设施,其通信质量的好坏直接关系到铁路的行车安全。本论文主要介绍无线通信的特点和我国无线列调通信系统的现状、构成、作用、功能、制式及工作频率,同时提出本文研究的意义和文章组成。     

Towards railway traffic management using switching Max-plus-linear systems

In this paper we present a railway traffic model and a model predictive controller for online railway traffic management of railway networks with a periodic timetable. The main aim of the controller is to recover from delays in an optimal way by changing the departure of trains, by breaking connections, by splitting joined trains, and - in the case of multiple tracks between two stations - by redistributing the trains over the tracks. The railway system is described by a switching max-plus-linear model. We assume that measurements of current running and dwell times and estimates of future running times and dwell times are continuously available so that they can be taken into account in the optimization of the system’s control variables. The switching max-plus-linear model railway model is used to determine optimal dispatching actions, based on the prediction of the future arrival and departure times of the trains, by recasting the dispatching problem as a Mixed Integer Linear Programming (MILP) problem and solving it. Moreover, we use properties from max-plus algebra to rewrite and reduce the model such that the MILP problem can be solved in less time. We also apply the algorithm to a model of the Dutch railway network.     

A fuzzy Petri net model to estimate train delays

Even with the most accurate timetable, trains often operate with delays. The running and waiting times for trains can increase unexpectedly, creating primary delays that cause knock-on delays and delays for other trains. The accurate estimation of train delays is important for creating timetables, dispatching trains, and planning infrastructures. In this work, we proposed a fuzzy Petri net (FPN) model for estimating train delays. The FPN model with characteristics of hierarchy, colour, time, and fuzzy reasoning was used to simulate traffic processes and train movements in a railway system. The trains were coloured tokens, the track sections were termed places, and discrete events of train movement were termed transitions. The train primary delays were simulated by a fuzzy Petri net module in the model. The fuzzy logic system was incorporated in the FPN module in two ways. First, when there were no historical data on train delays, expert knowledge was used to define fuzzy sets and rules, transforming the expertise into a model to calculate train delays. Second, a model based on the Adaptive Network Fuzzy Inference System (ANFIS) was used for systems where the historical data on train delays were available (from detection systems or from the train dispatcher’s logs). The delay data were used to train the neuro-fuzzy ANFIS model. After the results of the fuzzy logic system were verified, the ANFIS model was replicated by a fuzzy Petri net. The simulation was validated by animating the train movement and plotting the time-distance graph of the trains. Results of the simulation were exported to a database for additional data mining and comparative analysis. The FPN model was tested on a part of the Belgrade railway node.     

A Train Dispatching Model Under a Stochastic Environment: Stable Train Routing Constraints and Reformulation

After major capacity breakdown(s) on a railway network, train dispatchers need to generate appropriate dispatching plans to recover the impacted train schedule from perturbations and minimize the expected total train delay time under stochastic scenarios. In this paper, we propose a cumulative flow variables-based integer programming model for dispatching trains under a stochastic environment on a general railway network. Stable Train Routing (STR) constraints are introduced to ensure that trains traverse on the same route across different capacity breakdown scenarios, which are further reformulated to equivalent linear inequality constraints. Track occupancy and safety headways are modelled as side constraints which are dualized through a proposed Lagrangian relaxation solution framework. The original complex train dispatching problem is then decomposed to a set of single-train and single-scenario optimization subproblems. For each subproblem, a standard label correcting algorithm is embedded for finding the time dependent least cost path on a space-time network. The resulting dual solutions can be transformed to feasible solutions through priority rules. Numerical experiments are conducted to demonstrate the efficiency and effectiveness of the proposed solution approach.     

基于GPS的铁路养路车监控系统的总体研究

车辆监控系统是集电子技术、通信技术和数据库技术在交通管理领域广泛应用而产生的一个崭新的领域。本设计利用现有的GPS技术,针对铁路大型养路车设计出养路车在线监控系统。它从铁路提速的实际情况出发,综合考虑了人、车、路等方面的因素,为铁路维修质量的提高和工作人员的操作方便提出了一系列解决方案,大大完善了大型养路车数据处理的功能,增强了人机的交互能力。本文首先将GPS技术结合运用到系统设计中,并且提出了一个基于GPS的养路车监控系统的设计方案。该监控系统是由下位机的车载终端系统、通讯服务器系统和上位机的监控终端系统三大部分组成,下位机负责数据采集;上位机负责数据显示、数据分析和数据处理;服务器负责连接上下终端的数据传送。     

A high speed railway control system based on the fuzzy control method

This paper proposed a high-speed railway control system based on the fuzzy control method. The fuzzy control system of the high-speed railway is designed in the Matlab software according to the expert experience and knowledge. At first the input and output variables have been fuzzified in the fuzzification process. Then the membership function is designed and the control rules are discussed in detail bring into correspondence with expert knowledge. The parameters discussion about the maximum speed and traction effort are studied in detail. Finally, the defuzzify process can output the results directly to control the high speed railway train. The results indicated that the fuzzy control system is effective and accurate in the high speed railway control process.     

基于硬时间窗的技术站解编方案综合协调优化

针对现有制定的解编方案无法有效地满足铁路技术站阶段计划配流工作,基于牵引质量和换长的不同硬时间窗满轴约束,并综合考虑车流接续和编组去向约束,以总车流量、满轴出发列车最多为目标,建立了技术站多目标动态配流模型。为实现解编方案综合协调优化,依据解体和编组顺序调整规则,并通过定义可解集合和改进蚁群算法的状态转移规律及信息素更新策略,设计了一种基于蚁群算法的辅助决策支持系统。算例表明该辅助决策支持系统可以缩小配流问题规模,帮助决策者选择满意的解编配流方案,同时可以考虑解编顺序的改变对配流结果带来的影响,做到解体照顾编组,从而为实现铁路技术站调度系统的综合协调优化提供理论支持。     

高速铁路运行控制与动态调度一体化的现状与展望

高速铁路运行控制系统是高速铁路的大脑和神经系统, 对列车的安全和高效运行至关重要. 随着我国高铁里程数和客运量的快速增加, 现有的控制手段和调度方法在快速、有效解决列车运行过程中出现的突发事件(比如电力故障、突发地震、山体滑坡、异物侵限等)方面尚有一定差距. 目前列车运行控制与调度采用分层架构, 突发情况下主要依赖调度员和司机的人工经验进行应急处置, 列车晚点时间较长, 旅客满意度不高. 因此, 如何针对高速列车运行过程中可能出现的突发事件, 提升其应急处置能力, 成为保障高铁安全高效运营的一大难题. 本文围绕高铁运行控制与动态调度一体化这一前沿研究热点, 对现有运行控制和动态调度的发展现状进行梳理, 在此基础上给出一体化的基本架构, 明确其基本内涵, 最后提出了未来的主要研究方向.     

基于实例的客运站股道运用实时决策推理方法*

客运站股道运用实时决策问题是一个半结构化问题,实时决策推理研究为解决特殊情况下铁路客运站实时决策问题提供理论基础,具有十分重要的现实意义。采用物元理论,构建基于实例的实时决策推理物元模型,将实时决策物元分为列车物元、方案物元和推理物元,结合车站调度员解决特殊情况下股道运用实时决策的思维过程,采用优度评价法和基于双空间模型的归纳学习法,设计基于实例的实时决策推理算法和自学规则算法,提出铁路客运站股道运用实时决策推理方法,用于制订特殊情况下的实时决策方案。实例分析结果表明,所提出的模型与算法能有效解决特殊情况下客运站股道运用实时决策问题,提高了股道运用实时决策的智能化水平。     

An Advanced Real-Time Train Dispatching System for Minimizing the Propagation of Delays in a Dispatching Area Under Severe Disturbances

In highly utilized rail networks, as in the Netherlands, conflicts and subsequent train delays propagate considerably in time and space during operations. In order to realistically forecast and minimize delay propagation, there is a need to extend short-term traffic planning up to several hours. On the other hand, as the magnitude of the time horizon increases the problem becomes computationally intractable and hard to tackle. In this paper, we decompose a long time horizon into tractable intervals to be solved in cascade with the objective of improving punctuality. We use the ROMA dispatching system to pro-actively detect and globally solve conflicts on each time interval. The future evolution of railway traffic is predicted on the basis of the actual track occupation, the Dutch signaling system and dynamic train characteristics. Extensive computational tests are carried out on the railway dispatching area between Utrecht and Den Bosch.     

Non-Discriminatory Automatic Registration of Knock-On Train Delays

Incidents and waiting for train connections are registered by dispatchers as sources of train delays, but route and headway conflicts are not always clearly recognized. Moreover, traffic management and route setting are the primary task of dispatchers and signallers, whilst monitoring and incident registration is not allowed to take up too much of their time. This paper describes a tool that automatically and without discrimination identifies route conflicts and the train numbers involved. It is based on standard train describer and infrastructure messages recorded on the Dutch railway network. The logic of these messages is captured in a coloured Petri net (CPN) model on which a prototype tool for route conflict identification and estimation of knock-on delay has been developed.     

Future train traffic control: control by re-planning

Improving train traffic control can be a cost-efficient way to improve train traffic punctuality and increase utilization of existing and future railway infrastructure. However, performance in train traffic control tasks currently involves working on a technical level in order to regulate the traffic flow. Working in a preventive manner is poorly supported and train traffic controllers are usually restricted to just solving problems as they occur. This often results in unnecessarily long delays and decreased timeliness of train traffic. The main objective of this paper is to describe a proposed control strategy and a case study, which evaluates the control strategy and the prototype tool derived from the research. By shifting the control paradigm to a high-level control strategy, many of today’s problems may be avoided, with benefits of the reduction in delays, improved timeliness and better utilization of the infrastructure. Twenty-one train traffic controllers participated in a case study, with a simulated prototype environment. The majority of the participating train traffic controllers were positive to the new concepts and ideas. Many of the important aspects of the proposed control strategy can be investigated with the simulation, but due to the complexity of train traffic some issues must be evaluated in an operative environment.     

Challenges to multiteam system leadership: an analysis of leadership during the management of railway disruptions

Rail traffic is controlled by operators working in multiple control centres. Although each of these control centres enjoy quite some autonomy and authority, their activities are highly interdependent. This is especially the case during the management of disruptions. In this study, we look at the role of leader teams with system-wide responsibilities and the task of synchronizing the control centres’ activities. Research on leadership in this multiteam setting of networked control centres, which operate in a dynamic and time-compressed environment, is limited. Hence, this study explores the behaviours and functions of these leader teams during the management of two large-scale disruptions in the Dutch railway system. We will show how various factors influence the ability to provide leadership within this specific real-world context. This study demonstrates that combining insights from the literature on multiteam systems and resilience engineering can contribute to our knowledge of the critical challenges of control in polycentric adaptive systems.

     

Ergonomic design of a railway traffic control room: A Serbian experience

The aim of the research presented in this paper is to perform an ergonomic evaluation of compatibility between control desk, display panel, and their control devices with operators’ capabilities in the process of railway traffic control. This paper covers the application of ergonomic criteria for designing the control room and its main elements, functional characteristics of operators, and the influence of illumination on operator’s work efficiency. The paper also introduces methodologies for anthropometric and kinesiological analysis of operators, ergonomic analysis of control desk and display panel, and analysis of illumination in the Railway Traffic Control Room in Nis, Serbia. The research also includes basic statistical parameters for body measures of operators, configuration, and dimension of control desk as a unit, ergonomic analysis of control desk buttons, ergonomic analysis of display panel and its elements, parameters for illumination level of control room, control desk and display panel, and uniformity of illumination and brightness. To establish a link between these research and cognitive demands, methods of cognitive analysis of control and management activities in control room and decision making in abnormal situation by using an operator’s stress model are presented. The importance of this approach is that ergonomic assessment of current condition will determine the inadequate design and the ergonomic approach to be used in the implementation of the analysed control room. The results given in this paper enable the beginning of reconstruction and design of new elements in the control room, which will lead to abettor optimized control of railway traffic.     

超限车运行对双线铁路运能损失影响分析

以双线自动闭塞区段列车追踪运行为对象,充分考虑超限车运行特征,采用元胞自动机理论,提出列车运能换算、站元胞等概念;设计双线铁路列车运行的各种变换规则,分析超限车越行和禁会前后的元胞状态,构建基于CA的双线铁路列车运行仿真模型和运能损失评估模型,模拟双线区段列车运行过程,刻画超限车运行所引起的耗能特征。仿真结果表明,双线区段减少一个禁会区间时,上行方向通过能力可以少浪费15.2%,下行方向通过能力可以少浪费6.3%;综合考虑双线区段通过能力及其输送能力时,上行方向运能可以少浪费18.5%,下行方向运能可以少浪费8.8%;提出的方法能全面分析超限车运行对双线铁路运能的影响,评估超限车运行对双线铁路运能损失,为合理铺化双线铁路区段的列车运行图提供决策支持。     

A New Methodology for Modeling, Analysis, Synthesis, and Simulation of Time-Optimal Train Traffic in Large Networks

From a system-theoretic standpoint, a constrained state-space model for train traffic in a large railway network is developed. The novelty of the work is the transformation or rather reduction of the directed graph of the network to some parallel lists. Mathematization of this sophisticated problem is thus circumvented. All the aspects of a real network (such as that of the German rail) are completely captured by this model. Some degrees of freedom, as well as some robustness can be injected into the operation of the system. The problem of time-optimal train traffic in large networks is then defined and solved using the maximum principle. The solution is obtained by reducing the boundary value problem arising from the time-optimality criterion to an initial value problem for an ordinary differential equation. A taxonomy of all possible switching points of the control actions is presented. The proposed approach is expected to result in faster-than-real-time simulation of time-optimal traffic in large networks and, thus, facilitation of real-time control of the network by dispatchers. This expectation is quantitatively justified by analysis of simulation results of some small parts of the German rail network.