Prediction of railway power demand

The short-term prediction problem is considered for power demand at railway energy supply stations of the Dutch national railway company. A model and an adaptive prediction algorithm are presented. The algorithm is based on a self-tuning predictor for the output of a Gaussian system.     

Efficient verification of railway infrastructure designs against standard regulations

In designing safety-critical infrastructures s.a. railway systems, engineers often have to deal with complex and large-scale designs. Formal methods can play an important role in helping automate various tasks. For railway designs formal methods have mainly been used to verify the safety of so-called interlockings through model checking, which deals with state change and rather complex properties, usually incurring considerable computational burden (e.g., the state-space explosion problem). In contrast, we focus on static infrastructure models, and are interested in checking requirements coming from design guidelines and regulations, as usually given by railway authorities or safety certification bodies. Our goal is to automate the tedious manual work that railway engineers do when ensuring compliance with regulations, through using software that is fast enough to do verification on-the-fly, thus being able to be included in the railway design tools, much like a compiler in an IDE. In consequence, this paper describes the integration into the railway design process of formal methods for automatically extracting railway models from the CAD railway designs and for describing relevant technical regulations and expert knowledge as properties to be checked on the models. We employ a variant of Datalog and use the standardized “railway markup language” railML as basis and exchange format for the formalization. We developed a prototype tool and integrated it in industrial railway CAD software, developed under the name RailCOMPLETE^®. This on-the-fly verification tool is a help for the engineer while doing the designs, and is not a replacement to other more heavy-weight software like for doing interlocking verification or capacity analysis. Our tool, through the export into railML, can be easily integrated with these other tools. We apply our tool chain in a Norwegian railway project, the upgrade of the Arna railway station.     

Discrete-event models of a railway network

This paper constructs discrete-event models for the basic elements of railway networks, i.e., a station-to-station block with a passing track, a segment (as a part of a station-tostation block), a segment section (a block section), a railway point, as well as train operation models. All models represent Petri nets with bounding arcs. The group control of the models under the parallel-conveyor movements of trains is implemented by special control elements (the so-called supervisors) that ensure railway traffic safety requirements.     

基于梯形逻辑的联锁系统形式化验证方法

铁路联锁系统设计通常采用梯形逻辑进行建模。为了实现对铁路联锁系统进行形式化验证的目的,根据梯形逻辑的状态变迁语义,将梯形逻辑表示的联锁系统模型转换成模型检测工具NuSMV的语言,并将铁路联锁系统的安全需求表示为计算树逻辑(CTL),最后实现基于NuSMV的铁路联锁系统设计模型的形式化验证。     

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.     

TETRA在城市轨道交通无线通信系统中的应用

随着经济的发展,轨道交通是解决大城市交通拥挤的一种有效措施.在介绍了TETRA数字集群技术的特点及其强大功能后,分析了轨道交通无线通信系统的特点和功能,并结合重庆轻轨较新线一期工程项目,给出了其在城市轨道交通通信系统中的应用.从而更进一步地说明了TETRA数字集群技术是轨道交通无线通信系统的发展方向.     

高速铁路通信系统方案研究综述

随着科学技术的不断发展,信息化的全面推进是当今世界的发展的大趋势,我国也进入了信息全球化的发展进程.由于公共通信系统的长时间发展与研究,已经进入到相对成熟的时期,而高速铁路通信系统无论使用环境还是在系统的组成上都有很大的差距.所以对高速铁路通信系统进行的研究,是当今铁路通信部门应当重视的问题.     

铁路物流企业信息平台的研究与构建

相比其他物流企业,铁路物流企业更需要建立信息平台来增强物流业务的整合能力,准确掌握运输生产信息,并充分共享铁路运输管理信息系统(TMIS)提供的具有核心竞争力的资源。结合现代物流信息系统理论,针对铁路物流企业的特点,研究并构建了铁路物流企业信息平台,对该平台的系统结构、逻辑结构和网络结构等进行了详细设计和实现。     

基于通信系统的铁路信号信息传输的安全性研究

国家铁路“十一五”规划对高速铁路的发展提出了更多的要求,要实现这一要求,铁路信号信息的安全传输是至关重要的一个条件。笔者结合自身工作介绍铁路信号信息传输的故障——安全定义,分析了传输方式的选择,探讨了铁路信号安全信息传输系统的设计方案。     

A fuzzy reasoning and fuzzy-analytical hierarchy process based approach to the process of railway risk information: A railway risk management system

Risk management is becoming increasingly important for railway companies in order to safeguard their passengers and employees while improving safety and reducing maintenance costs. However, in many circumstances, the application of probabilistic risk analysis tools may not give satisfactory results because the risk data are incomplete or there is a high level of uncertainty involved in the risk data. This article presents the development of a risk management system for railway risk analysis using fuzzy reasoning approach and fuzzy analytical hierarchy decision making process. In the system, fuzzy reasoning approach (FRA) is employed to estimate the risk level of each hazardous event in terms of failure frequency, consequence severity and consequence probability. This allows imprecision or approximate information in the risk analysis process. Fuzzy analytical hierarchy process (fuzzy-AHP) technique is then incorporated into the risk model to use its advantage in determining the relative importance of the risk contributions so that the risk assessment can be progressed from hazardous event level to hazard group level and finally to railway system level. This risk assessment system can evaluate both qualitative and quantitative risk data and information associated with a railway system effectively and efficiently, which will provide railway risk analysts, managers and engineers with a method and tool to improve their safety management of railway systems and set safety standards. A case study on risk assessment of shunting at Hammersmith depot is used to illustrate the application of the proposed risk assessment system.     

铁路集装箱转运作业问题的决策支持模型研究

集装箱转运问题是铁路集装箱物流中心站提高服务效率的关键问题之一,转运过程中涉及到的相关资源配置则是其要解决的核心内容。针对集装箱转运作业流程的特点,利用系统分析方法将转运系统分成门式起重机、内部集装箱运输卡车和正面吊运机/辅助箱场三个子系统,分别对各子系统进行操作时间分析,进而得到整体系统的作业时间模型,由此开发集装箱转运问题的规划调度决策支持系统,为决策者提供决策依据。通过模拟运行结果,得到了集装箱转运过程中所需的所有设备资源的最优组合数量,将模型模拟结果与相应的实际数据进行对比,证明了该模型的可行性。     

基于高速铁路通信的多波束机会波束赋形技术

鉴于高速铁路通信中,列车位置信息可预测、列车车顶中继转发天线数有限,以及反馈信息时延大、多普勒衰落较大、频繁切换等特性,传统的波束赋形并不适用于高速铁路场景。位置信息辅助的多波束机会波束赋形能够利用列车位置信息可预测的优势,在机会波束赋形算法中有效地提高发送波束随机相位与来波相位匹配的概率,同时支持多个波束并行传输,以多波束选择实现更好的多用户分集增益,且机会波束赋形无需反馈完全信道状态信息。因此位置信息辅助的多波束机会波束赋形技术适用于高速铁路通信。     

基于浮空器雷达的公路铁路积累方法研究及比较

针对“低慢小”目标的威胁,让雷达升空成为近年来雷达发展的一种新趋势,但随着雷达升空,杂波干扰问题也随之而来,特别是地面上高速运动的汽车、火车等,都易于成为虚假目标,影响操作员的判断.而传统的电子公路图铁路图又难以适应不断深入的公路铁路基础建设的发展.针对这一问题,研究了基于浮空器雷达的公路铁路积累方法,利用雷达回波的点迹信息积累生成实时的公路铁路图,用于辅助操作员进行判断,尽快丢弃在公路或铁路上行驶的虚假目标.还在雷达检飞过程中比较了不同坐标系下的公路铁路积累效果,实验结果表明,基于极坐标系下的公路铁路积累方法可以有效形成实时公路铁路积累图,从而辅助操作员快速辨别公路铁路上运动的目标.     

Heuristics for railway infrastructure saturation

This research concerns the problem of the evaluation of the railway infrastructure capacity. It is an important question when railway authorities have to choose between different infrastructure investment projects. We developped independently two heuristic approaches to solve the infrastructure saturation problem. The first is based on a constraint programming model which is solved using a greedy heuristic. The second approach identifies the saturation problem as a unicost set packing problem and its resolution is ensured by an adaption of GRASP metaheuristic. Currently, both resolution techniques are not in competition. The goal is to grasp the resolution ability of the heuristics and to analyse the kind of solutions produced. The Pierrefitte-Gonesse junction has been used as experimental support. A software environment allows to simulate several timetables involving TGV, Inter City and Freight trains.     

Estimation of railway vehicle suspension parameters for condition monitoring

This paper investigates the problem of parameter estimation for railway vehicle suspensions so as to provide information to support condition-based (instead of calendar-based) maintenance. A simplified plan view railway vehicle dynamical model is derived and a newly developed Rao–Blackwellized particle filter (RBPF) based method is used for parameter estimation. Computer simulations are carried out to assess and compare the performance of parameter estimation with different sensor configurations as well as the robustness with respect to the uncertainty in the statistics of the random track inputs. The method is then verified practically using real test data from a Coradia Class 175 railway vehicle with only bogie and body mounted sensors, and some preliminary results are presented.     

Robustness for a single railway line: Analytical and simulation methods

Railway scheduling has been a significant issue in the railway industry. Over the last few years, numerous approaches and tools have been developed to compute railway scheduling. However, robust solutions are necessary to absorb short disruptions. In this paper, we present the robustness problem from the point of view of railway operators and we propose analytical and simulation methods to measure robustness in a single railway line. In the analytical approach, we have developed some formulas to measure robustness based on the study of railway line infrastructure topology and buffer times. In the simulation approach, we have developed a software tool to assess the robustness for a given schedule. These methods have been inserted in MOM (More information can be found at the MOM web page http://www.dsic.upv.es/users/ia/gps/MOM), which is a project in collaboration with the Spanish Railway Infrastructure Manager (ADIF).     

OTN技术在城市轨道交通通信系统中的应用

介绍了OTN技术的特点及其强大功能,并结合重庆轻轨较新线一期工程项目,给出了其在城市轨道交通通信系统中的应用,进一步地证明了OTN技术的先进性,从而为城市轨道交通中的通信系统的设计与实现提供了依据.     

基于组合遗传算法的铁路危险货物办理站点整合优化

铁路危险货物办理站点作为铁路危险货物运输基础设施之一,其选址布局、建设规模和职能分工的合理性对于提高铁路危险货物运输效率、满足运输需求和环境风险控制目标都至关重要。为了有效解决铁路危险货物办理站点整合优化的多目标选址—分派模型组合方案规模庞大、计算困难的问题,采用了组合遗传算法对此问题进行优化。算例结果显示,该算法具有收敛速度快、运行稳定的特点,能够有效解决相关问题。     

A Fuzzy Petri Nets approach for railway traffic control in case of abnormality: Evidence from Taiwan railway system

Railway traffic control by dispatchers in case of abnormality is critical to assure the service quality of a railway system’s operation. However, this unique professional knowledge often lies in the dispatcher’s mind. Therefore, this study aims to transform a train dispatcher’s expertise into a useful knowledge rule. The fuzzy Petri Net approach is adopted to formulate the decision rules of train dispatchers in case of abnormality as the basis for future development of a dispatching decision support system. The dispatching decision rules, factors, and possible options when perturbation happens are collected via expert interviews and literature reviews. This study discusses the abnormal scenarios, including centralized traffic control system failure, automatic train protection failure, and locomotive failure. A case study of a line section of Taiwan’s railway network is implemented and the empirical result could be used as a reference in railway dispatching in case of abnormality.