Block Signaling System Research Articles

Цифровые технологии пропуска по перегонам и станциям — основа организации движения на Московских центральных диаметрах

train separation, automatic block system, ABTC-MSh system, moving block, interlocking, automatic cab signalling, train control system The article discusses the development of automatic block systems, which form the basis of separation systems. It also highlights the key factors limiting the capacity on open lines, and ways to solve them. A brief overview of the foreign experience of the organization of train separation using automatic block system based on track circuits is given. The article shows the capabilities and role of the computerbased automatic block signalling system with a centralized placement of equipment, audio frequency track circuits and duplicating information transmission channels as an important element of the train traffic management at the sections of Moscow Central Diameters. The significance of the implemented non-stop passage of trains along the main station tracks providing substantial section capacity increase is demonstrated. The necessity of building a digital system for train spacing is shown, which makes it possible to implement the moving block technology with-in the station ensuring the movement of trains on open lines and at stations with the same headway. The advantages of a new type of the computer-based automatic block signalling system as a basic element of a promising Russian train traffic control system and the positive effects of its implementation on the Russian railway network are indicated. The direction of development of train separation systems is outlined within the framework of further digitalization.

Proposing a Train Speed Profile Generation Method in Railway Signalling Systems Based on Internet of Things (IoT): Performance and Stability Assurance

In the past years, the Internet of Things has created tremendous changes in various industries, including transportation systems and especially railway signalling systems. One of the issues that is very important in signalling systems is the design of trains speed profiles to control the movement of trains based on the defined headway and line conditions such as other trains positions. Information packet loss is one of the issues that should be considered in the field of Internet of Things and if this issue occurs, effective solutions should be adopted in the system for optimal performance. In this article, a method for generating speed profiles for moving block signalling systems in case of packet loss is proposed and the stability of the system is checked using the proposed method. Finally, we will implement the proposed method on a part of a railway line and examine the results.

Modeling the Duration of the Impact of Unplanned Disruptions on Passenger Trips Using Smartcard Data in Urban Rail Systems

Many urban rail systems operate near capacity given the rapid increase in passenger demand, and unplanned disruptions are unavoidable. From a passenger perspective, the duration of trip delays is a major concern, and passenger trip delays may be longer than the train delays. Several studies have focused on predicting train delays, but the research on the duration of the disruption impacts on passenger trips is limited given that the duration is not observed directly. This paper proposes a probabilistic method to estimate the disruption impact duration using smartcard data, explores statistical and machine learning models to predict the duration of impacts on passengers, and identifies influencing factors including incident characteristics, operating conditions, infrastructure, external factors, and demand. The results highlight that prediction accuracies are acceptable for multiple linear regression, accelerated failure time, and random forest models. Disruptions caused by power failures have longer impact durations than other causes, followed by platform screen doors. The fixed block signaling system leads to a larger disruption duration than the moving block system. The study provides, for the first time, a data-driven approach to understanding the duration of the impact of disruptions on passenger trips using smartcard data which can facilitate timely and informed decision-making under unplanned disruptions.

Onboard train speed optimization for energy saving using the prediction of block clearing times under real-time rescheduling

Energy-saving driving is crucial during railway operation, especially in case of disturbances that require timetable rescheduling. This paper presents a method for the dynamic onboard tuning of energy-efficient speed profiles after the real-time train rescheduling process under a fixed block signaling system for mixed traffic. Similar to the idea of connected driver advisory systems, trains constantly communicate with a central traffic management system. After the rescheduling process, this system provides recommended time corridors for the passing of block signals that depend on the predicted clearing times of the block sections. These recommendations are then used for individual energy optimization of single train runs by avoiding unnecessary braking in front of block signals and maximizing cruising distances. The method is tested and evaluated on a representative line segment of the ELVA, the Railway Signaling Lab at RWTH Aachen University under realistic conditions. Energy consumptions are compared for different prediction time horizons at which the recommendations are available to the train's onboard system. In the examined test case of two trains, the energy-consumption could be decreased by up to 53% compared to operation without any rescheduling system. Thus, the proposed method is able to reduce energy consumption significantly.

A Methodology Framework for Modelling a Rail Moving Block System

In the railway field, rigorous development processes contribute to implement safe and efficient systems. Railway safety standards recommend the use of formal modelling and verification techniques to guarantee processes’ correctness and validate safety requirements. ERTMS/ETCS L3 (European Railway Traffic Management System / European Train Control System Level 3) is a European standard for interoperable railways based on the concept of Moving Block signaling systems which allows for substantial capacity gains and reduced costs. In this paper, we explain why the ETCS L3 struggles to be deployed despite the benefits it can bring. Then, we discuss the planned implementations of ETCS L3 at a European-wide scale. Finally, we present a methodology framework using formal models to verify moving block systems. This work is performed in the context of the PERFORMINGRAIL European project.

Macroscopic traffic flow in railway systems — A discussion of the applicability of fundamental diagrams

Macroscopic traffic flow theory is widely used to analyze the performance and congestion in transportation systems and urban traffic. Currently, the main area of application is road traffic, where fundamental diagrams depicting the relationship between performance parameters such as traffic density, traffic flow and vehicle speed are used to represent traffic regimes and system settings. Research on the applicability for rail traffic systems is only starting to emerge and has mainly focused on mass transit systems and moving block signaling systems, so far. The current paper provides a theoretical analysis of traffic flow properties on unidirectional railway lines. Macroscopic fundamental diagrams are established and used to analyze similarities and differences of traffic flow behavior in railway systems. It is shown how fundamental diagrams allow to pinpoint flow regimes and different phases in train traffic, which can be useful information for system design and operation planning. Railway systems are studied both in a deterministic setting allowing to analyze peak efficiency and in a stochastic setting with perturbations.

State movement for controlling trains operating under the virtual coupling system

Train Virtual Coupling System (VCS) has been proposed as a new signalling system for controlling trains by building a group of trains as convoys in order to increase line’s capacity. This is achieved because the consecutive trains under the VCS is separated only by a relative braking distance; this is much shorter than the separation distance required in the Fixed Block Signaling (FBS) and Moving Block Signaling systems (MBS). In order to achieve the high capacity obtained from the VCS, the trains in a virtually coupled convoy should keep at a distance as close to the relative braking distance as possible and run at the same speed for maintaining the safe distance between them. In this paper, we propose a distance and velocity difference approach and introduce the multiple state movements for stimulating train’s movement under the VCS. The simulated results show that the capacity can be significantly increased and maximized in which the actual separation distance between trains when they are in convoy state is slightly longer than the minimum safe distance. It could be ensured that the train has proceeded safely in that the actual separation distance is surely longer than the minimum safe distance throughout the operation time period. In addition, we show that the trains can also proceed smoothly, in that a following train catches up with its leading train and joined in the convoy with a stable movement.

Coordinated Control in the Presence of Actuator Saturation for Multiple High-Speed Trains in the Moving Block Signaling System Mode

This paper studies coordinated control of multiple high-speed trains (HSTs) in the presence of actuator saturation. For HSTs operating on a railway line under the moving block signaling system (MBS) mode, adjacent trains are connected directly through train-to-train (T2T) wireless communication such that each train exchanges information with the adjacent trains that are inside its communication range, making all trains in a railway line a multi-agent system. A state-dependent undirected graph is introduced to depict the underlying communication topology. Coordinated control laws are established that, in addition to achieving consensus among trains at the reference displacement and speed profile and avoiding collision, preserve communication connectivity. It is worth mentioning that, for each train, only the position information from its neighboring trains is needed to cause speed and displacement consensus. The effectiveness of our proposed control laws are verified by simulation study.

Design and Implementation of a Control, Monitoring and Supervision System for Train Movement Based on Fixed Block Signaling System with AVR Microprocessor

Railway signaling and control systems are vital for the safe control of transport processes in rail traffic. Today, industry uses many processes, such as railway signaling systems, that must be controlled. Manufacturers of such systems have tried to update their products in line with modern industrial control technologies. In this paper, the possibility of using the common industrial automation equipment for a signaling system are investigated. Different parts of the signaling system, including wayside equipment, field element controls (interlocking and object controller) and supervision systems were specified. Then, the interlocking logic was extracted based on a fixed block signaling system. Control, monitoring and supervision systems were designed with an AVR microcontroller and then implemented on printed circuit board. Finally, the outputs of the system and its results with various railway lines, based on chosen layout, were analyzed and its applications identified. These applications include wayside equipment monitoring, the training of traffic control operators, and movement safety tests of the line before setup of the main system.

Cooperative Prescribed Performance Tracking Control for Multiple High-Speed Trains in Moving Block Signaling System

If high-speed trains move under a moving block signaling (MBS) system, it is a quite challengeable and significant issue to cooperate the multiple high-speed trains, such that they are separated safely and governed steadily. As an intelligent, comprehensive, and advanced modern train operation control system, the MBS system will definitely, in the near future, replace the widely used fixed block signaling system due to its modern communication, multi-source positioning, and advanced control method. Due to the involvement of several subsystems and lots of track-side equipment, such as radio block center (RBC), global system for mobile communications-railway (GSM-R), and so on, it is a nontrivial task to develop a reliable MBS system under complex operational environments, particularly without a pivotally cooperative control method for the movement of multiple high-speed trains. This paper addresses the cooperative control for multiple high-speed trains to achieve prescribed performance tracking, i.e., the speed and the position of high-speed trains are guaranteed to be confined to specific speed limitations and allowed distances ratified by automatic train protection and moving authority, respectively. The proposed control requires no prior information of the empirical parameters of the operational resistances and online adjusts by proper adaptation laws. Theoretical analysis and simulation results are given to demonstrate the effectiveness of the proposed control methods.

Increasing the traffic capacity of railway blocks

The paper considers ways of increasing the traffic capacity of railway sections equipped with automatic block signaling systems, with a discrete variable number of block sections. Simultaneous traffic of long and short trains on a single block is analyzed. The paper highlights shortcomings and limitations of the existing automatic block signaling systems, including low traffic capacity and non-compliance with traffic safety requirements for railway sections. The study is aimed at removing these shortcomings and limitations. For this purpose, a reasonable technical solution has been presented, analyzed and scientifically grounded. System analysis techniques have been used to study the performance of traffic control devices.

Truck circuits diagnosis for railway lines equipped with an automatic block signalling system

This work presents a diagnosis method for detecting track circuits failures on a railway traffic line equipped with an Automatic Block Signalling installation. The diagnosis method uses the installation’s electrical schemas, based on which a series of diagnosis charts have been created. Further, the diagnosis charts were used to develop a software package, CDCBla, which substantially contributes to reducing the diagnosis time and human error during failure remedies. The proposed method can also be used as a training package for the maintenance staff. Since the diagnosis method here does not need signal or measurement inputs, using it does not necessitate additional IT knowledge and can be deployed on a mobile computing device (tablet, smart phone).

Energy-Efficient Train Tracking Operation Based on Multiple Optimization Models

This paper studies the energy-efficient operation problem of two trains operating along the same line consecutively in urban trail transit (URT). In URT, a moving block signaling (MBS) system is utilized in which the following train's tracking target point is moving forward continuously with the leading train's running. In this case, the following train may be influenced by the leading train's exceptional situations, leading to energy wasting and arrival time delay. In order to reduce energy consumption and arrival delay for the following train, a multiple-optimization-model-based energy-efficient operation method is proposed and verified in this paper. The novelty of this paper lies on the establishment of a novel multiple-model-based switching optimization framework to reduce energy consumption while guaranteeing the punctuality during train tracking operation. More specifically, the operation status of the leading train is combined into the operation optimization for the following train, based on which eight energy-efficient tracking scenarios are discovered and classified into four optimization problems. Then, a general form of running phase sequence is designed to describe the energy-efficient train tracking operation strategy, and a new energy consumption function is proposed. Based on these, the four optimization problems are built into small-scale nonlinear programming models, which are computationally inexpensive and easy for online implementation. During the tracking process, the following train can obtain the energy-efficient strategies through switching among these four optimization models. In this framework, the following train is able to arrive at the next station by the fastest arrival time with lower energy consumption even when the arrival time is delayed by the leading train. Simulation results show the feasibility and effectiveness of the new method.

A Multiple Train Trajectory Optimization to Minimize Energy Consumption and Delay

In railway operations, if the journey of a preceding train is disturbed, the service interval between it and the following trains may fall below the minimum line headway distance. If this occurs, train interactions will happen, which will result in extra energy usage, knock-on delays, and penalties for the operators. This paper describes a train trajectory (driving speed curve) optimization study to consider the tradeoff between reductions in train energy usage against increases in delay penalty in a delay situation with a fixed block signaling system. The interactions between trains are considered by recalculating the behavior of the second and subsequent trains based on the performance of all trains in the network, apart from the leading train. A multitrain simulator was developed specifically for the study. Three searching methods, namely, enhanced brute force, ant colony optimization, and genetic algorithm, are implemented in order to find the optimal results quickly and efficiently. The result shows that, by using optimal train trajectories and driving styles, interactions between trains can be reduced, thereby improving performance and reducing the energy required. This also has the effect of improving safety and passenger comfort.

Multi-Agent Communication Based Train Control System for Indian Railways: The Structural Design

Indian Railways (IR) work on static block signaling (SBS) system to control mixed train traffic. Current state of operation can be improved by using communication based train control (CBTC) system with moving block signaling (MBS). The mixed traffic conditions in IR restrict the direct use of CBTC systems used elsewhere and thus first necessitated study of existing CBTC systems followed by development of CBTC system for IR. Operations research and constraint programming technologies do not cope well in complex, dynamic, and highly interactive systems like railway operations. Multi-agent systems are event based and have been used to express many complex real systems. Developments of multi-agent systems are based on logical structure design phase and implementation phase. Lack of sufficient standards and tools makes the design of complex agent based applications difficult thus most of the work do not describe the design phase in detail. This paper uses methodology for engineering systems of software agents (MESSAGE) for the analysis and design of multi-agent based CBTC system for IR. The paper describes the detail design of sub-goal moving authority given for the block section while considering various run time scenarios that might interrupt normal running of trains. A good structural design of the system shall however help for the study of behavioral aspects of the system through simulation or deployment.

Optimal design of energy-efficient ATO CBTC driving for metro lines based on NSGA-II with fuzzy parameters

One of the main priorities for metro line operators is the reduction of energy consumption, due to the environmental impact and economic cost. The new moving block signalling system CBTC (Communication Based Train Control) is being installed in order to increase the transport capacity of new metro lines, and to upgrade lines equipped with the former fixed block signalling systems. In addition, this new technology could be used to improve energy efficiency in the traffic operation, due to its capability to update the ATO (Automatic Train Operation) driving commands not only at stations but also along the journey.In this paper a new optimization algorithm is proposed to design ATO CBTC speed profiles to minimize energy consumption, generating the Pareto optimal curve. The algorithm is a multi-objective NSGA-II-F based on simulation of the train motion under uncertainty. The main source of uncertainty in the consumption calculation is the mass of the train, which is dependent on the passenger load, and it is modeled as a fuzzy number. In addition, a new method is proposed to fill running time gaps with dominated points, providing a pseudo-Pareto curve.The NSGA-II-F algorithm has been applied to design ATO CBTC optimal speed profiles in a case study of Metro de Madrid, providing additional energy savings up to 7.3% compared to former fixed block signalling systems and a well time-distributed pseudo-Pareto curve for the running times required by the traffic regulation system.

Energy saving for automatic train control in moving block signaling system

With rapid development of the railway traffic, the moving block signaling system (MBS) method has become more and more important for increasing the track capacity by allowing trains to run in a shorter time-headway while maintaining the required safety margins. In this framework, the tracking target point of the following train is moving forward with its leading train. This paper focuses on the energy saving tracking control of two successive trains in MBS. Nonlinear programming method is used to optimize the energy-saving speed trajectory of the following train. The real-time location of the leading train could be integrated into the optimization process. Due to simplicity, it can be used for online implementation. The feasibility and effectiveness are verified through simulation. The results show that the new method is efficient on energy saving even when disturbances present.

Optimal trajectory planning for trains under fixed and moving signaling systems using mixed integer linear programming

The optimal trajectory planning problem for multiple trains under fixed block signaling systems and moving block signaling systems is considered. Two approaches are proposed to solve this optimal control problem for multiple trains: the greedy approach and the simultaneous approach. In each solution approach, the trajectory planning problem is transformed into a mixed integer linear programming (MILP) problem. In particular, the objective function considered is the energy consumption of trains and the nonlinear train model is approximated by a piece-wise affine model. The varying line resistance, variable speed restrictions, and maximum traction force, etc. are also included in the problem definition. In addition, the constraints caused by the leading train in a fixed or moving block signaling system are first discretized and then transformed into linear constraints using piecewise affine approximations resulting in an MILP problem. Simulation results comparing the greedy MILP approach with the simultaneous MILP approach show that the simultaneous MILP approach yields a better control performance but requires a higher computation time. Moreover, the performance of the proposed greedy and the proposed simultaneous MILP approach is also compared with that of the greedy and the simultaneous pseudospectral method, where the pseudospectral method is a state-of-the-art method for solving optimal control problems. The results show that the energy consumption and the end time violations of the greedy MILP approach are slightly larger than those of the greedy pseudospectral method, but the computation time is one to two orders of magnitude smaller. The same trend holds for the simultaneous MILP approach and the simultaneous pseudospectral method.

Peak Power Demand and Energy Consumption Reduction Strategies for Trains under Moving Block Signalling System

In the moving block signalling (MBS) system where the tracking target point of the following train is moving forward with its leading train, overload of the substations occurs when a dense queue of trains starts (or restarts) in very close distance interval. This is the peak power demand problem. Several methods have been attempted in the literature to deal with this problem through changing train’s operation strategies. However, most existing approaches reduce the service quality. In this paper, two novel approaches—“Service Headway Braking” (SHB) and “Extending Stopping Distance Interval” (ESDI)—are proposed according to available and unavailable extra station dwell times, respectively. In these two methods, the restarting times of the trains are staggered and traction periods are reduced, which lead to the reduction of peak power demand and energy consumption. Energy efficient control switching points are seen as the decision parameters. Nonlinear programming method is used to model the process. Simulation results indicate that, compared with ARL, peak power demands are reduced by 40% and 20% by applying SHB and ESDI without any arrival time delay, respectively. At the same time, energy consumptions are also reduced by 77% and 50% by applying SHB and ESDI, respectively.

Automatic Interlocking Table Generation for Railway Stations using Symbolic Algebra

Interlocking is the most important component of a signalization system, which ensures safe travel and transportation. An interlocking system helps movement of trains on desired routes in fixed block signaling systems. The first step in the design of interlocking systems is to generate interlocking tables. Generation of interlocking tables for small scaled stations or railway yards can be realized easily. However, when the topology of the station is complicated, generation of the corresponding interlocking table becomes considerably difficult. In this study, a program that automatically generates interlocking tables for a given railway yard is explained. One of the main advantages of the program is that, switches and signal lights are placed automatically for a given station or railway yard depending on the topology.