Chinese Train Control System Research Articles

Reliability Analysis of CTCS-3 Train-Ground Communication System Based on 5G-R

The reliability of Chinese Train Control System Level 3 (CTCS-3) train-ground communication system is of great importance to ensure the safe operation of trains. The fifth Generation Mobile Communication for Railway (5G-R) is prospective for train-ground communication in the future. In this paper, the train-ground communication procedure of 5G-R (e.g., connection reestablishment, handover and train-ground data transmission) is tested by a semi-physical simulation platform. The test results, including the delay of different procedures together with the handover success rate, all can satisfy the quality of service (QoS) requirements. According to the communication procedure, deterministic and stochastic Petri net (DSPN) models of communication links and train-ground communication scenarios are established. Furthermore, the parameters of models are calibrated with the test data and protocol standards. We utilize <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pi$</tex-math></inline-formula> -tool to simulate and analyze the reliability of the train-ground communication system under the interaction of multiple fault factors. The results show that even in the worst handover scenario where the station distance is 1 km and the train speed is 400 km/h, the reliability of the train-ground communication system based on 5G-R can still reach 99.9963 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> . It not only meets the requirements of the train control services for the train-ground communication system, but also is better than the reliability of the GSM-R based communication system.

Feasibility Analysis of GSM-R System for Railways in Indonesia: Case Study of Jakarta Bandung High Speed Train

High-speed railway technology development necessitates the development of a communication system that supports various components of train operation facilities, such as train control, safety communication, and others. The construction of fhigh-speed railway in Indonesia in the Jakarta-Bandung area uses the Chinese Train Control System (CTCS) Level 3 signaling system, which makes the Global System for Mobile Communication-Railway (GSM-R) a wireless signaling network system. Because there are already existing GSM-based public telecommunications services, known as public GSM, on the same frequency used by a number of cellular operators in Indonesia, the use of GSM-R poses implementation challenges. This will result in reduced service quality and revenue for protected cellular network operators due to the use of these frequency bands to support the operation of high-speed railway services in Indonesia. In this study, an evaluation was carried out to look for other potentials from using the GSM 900 MHz frequency band, which can be used as an option to be implemented on high-speed trains in Indonesia. The research begins with calculating the estimated potential loss of revenue from using telecommunications network operators. This data will be analyzed in terms of the economic feasibility of several other frequency band choices for implementing the GSM 900 MHz frequency band on high-speed trains in Indonesia, so that it is hoped that this will become a new consideration that can become a solution and recommendation in the application and use of GSM-R technology in Indonesia.

Feasibility Analysis Of Gsm-R System For Railways In Indonesia: Case Study Of Jakarta Bandung High Speed Train

High-speed railway technology development necessitates the development of a communication system that supports various components of train operation facilities, such as train control, safety communication, and others. The construction of fhigh-speed railway in Indonesia in the Jakarta-Bandung area uses the Chinese Train Control System (CTCS) Level 3 signaling system, which makes the Global System for Mobile Communication-Railway (GSM-R) a wireless signaling network system. Because there are already existing GSM-based public telecommunications services, known as public GSM, on the same frequency used by a number of cellular operators in Indonesia, the use of GSM-R poses implementation challenges. This will result in reduced service quality and revenue for protected cellular network operators due to the use of these frequency bands to support the operation of high-speed railway services in Indonesia. In this study, an evaluation was carried out to look for other potentials from using the GSM 900 MHz frequency band, which can be used as an option to be implemented on high-speed trains in Indonesia. The research begins with calculating the estimated potential loss of revenue from using telecommunications network operators. This data will be analyzed in terms of the economic feasibility of several other frequency band choices for implementing the GSM 900 MHz frequency band on high-speed trains in Indonesia, so that it is hoped that this will become a new consideration that can become a solution and recommendation in the application and use of GSM-R technology in Indonesia.

Reliability prediction used dynamic Bayesian networks for redundant system with time‐lag correlation

AbstractIn the reliability prediction process of a redundant system, active units and standby units are assumed independent generally. Due to the interaction among units, failure of the active unit gives the standby unit a potential interior shock, then the standby unit fails after a period of operation. Therefore, the correlation between the active unit and the standby unit is triggered by the failure of the active unit and also has time‐lag. In this paper, a correlation estimated method with two parameters is proposed based on cross‐correlation analysis, where the two parameters are time‐lag interval and time‐lag correlation coefficient, the discriminant conditions of independent, simultaneous correlation and time‐lag correlation are given. Subsequently, the Conditional Probability Table (CPT) of Dynamic Bayesian Network (DBN) is updated by adding time‐lag intervals and time‐lag correlation coefficients. Then, DBN is optimized into Time‐lag Dynamic Bayesian Network (TDBN). Meanwhile, the modeling process and calculated method of TDBN are given. To reduce the complexity of TDBN, the maximum time‐lag correlation coefficient and the time‐lag interval corresponding are regarded as the main parameters to estimate time‐lag correlation. Finally, through the simulation analysis and the case of Chinese train control system (CTCS‐3), it could be seen that the reliability prediction of TDBN is more accurate than DBN, TDBN improves the reliability prediction accuracy of train and driver interface module to 0.8135 either.

The Search-Based Mutation Testing of the Chinese Train Control System Level 3 On Board a Train Control System

In this article, we combined a search-based technique with model-based mutation testing to overcome the inherent computational cost that comes with the test-case generation of the Chinese Train Control System Level 3 (CTCS-3) train control system by providing a newly designed fitness function to guide the search process of test cases. First, we defined the test-case inputs as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">timed input traces</i> , which can easily deal with noninput-enabled systems with both input events and input variables. Because the input sequence of the timed input traces can be potentially infinite, they can be more flexible in dealing with different scales of train control systems than can the traditional model-checking techniques. Furthermore, we proposed a way of encoding timed input traces as blocks of inputs for the genetic algorithm, together with crossover and mutation operators, to reduce the search space and improve algorithm efficiency. By using the encoded input blocks as individuals, the test cases generated from the train control system will be more compact and easier to perform. Finally, we applied the mutation operators to the mode-transition function of the CTCS-3 from which all of the known faults have been considered comprehensively. To evaluate the coverage of the test cases generated and compare the performance of different methods, the benchmarking indicators of conformance relation score (CRS), average CRS, and weighted CRS have all been analyzed. In addition, we performed an experiment to determine the extent to which the maximum block width can influence the search performance as a guidance for parameter selection in practice.

An Adaptive Dynamic Coding Method for Track Circuit in a High-Speed Railway

This article proposes an adaptive dynamic coding method for track circuits in the Chinese Train Control System of high-speed railways. This method will improve the resolution of the train control system in tracking circuits occupied by trains and give the existing automatic block system the basic characteristics of a virtual block and moving block, including block boundary virtual, length changing, position movement characteristics, and so on. Ultimately, using this method can expand capacity. Comparing the existing coding process of track circuits with the proposed method, this article describes the basic rules and working principles of adaptive dynamic coding of track circuits. Using the Beijing–Shanghai high-speed railway as an example, this article analyzes the effectiveness of this method in improving transportation capacity.

Crucial States Estimation in Radio Block Center Handover Using Petri Nets With Unobservable Transitions

The radio block center (RBC) is one of the most essential ground systems in a high-speed train control system both in Europe and in China. The RBC handover procedure is an important function of RBC, which affects the transport efficiency, reliability and safety of railways. Analysis of crucial states in the RBC handover procedure is helpful to determine whether there are potential risks in the procedure, and to locate the fault in time when a fault occurs. In this paper, we study a property, called C-detectability, of the RBC handover. This property has been defined in discrete event systems and requires that the crucial states can be determined uniquely by observing the system output. Taking the RBC handover procedure in the Chinese train control system level 3 (CTCS-3) as an example, we first model the RBC handover procedure using Petri nets, which are a graphical and mathematical modeling tool to formalize the behavior of discrete event systems. Then, based on the notion of basis reachability graph, an efficient approach is used to check C-detectability of the Petri net modeling the handover procedure. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The railway system is a safety-critical system. System safety is essential to the railway system. It is necessary to provide formal methods to model the system and analyze its properties. The motivation of this work is to present a general modeling framework of railway systems for the crucial states estimation. The crucial states estimation of the railway system has not been discussed yet in the literature despite its importance due to its relationship with the safety of the railway. In particular, estimating the crucial states in the railway system helps to determine whether there are potential risks in the system. In this paper, we investigate a new state estimation property (C-detectability), which is related to fault diagnosis, marking estimation and fault identification. Future research will consider the use of timed Petri nets to increase the modeling power and to allow the performance analysis of the railway system.

Evaluating operational risk for train control system using a revised risk matrix and FD-FAHP-Cloud model: A case in China

An accident caused by train control system may not only bring expensive loss, but also result in severe destruction to surrounding environment. The purpose of this study is to study operational risk of Chinese Train Control System- Level 3 (CTCS-3). An integrated risk assessment method is developed by combining fishbone diagram (FD), Fuzzy Analytic Hierarchy Process (FAHP) with cloud model. Based on fishbone diagram, risk factors (RFs) of train control system are identified from two perspectives of hazard event, namely occurrence frequency and sequence severity. To further classify RFs quantitatively, a revised risk matrix based on FAHP is introduced to calculate the consequence and likelihood weights for each risk factor (RF), and then Risk Index (RI) is getting by making product of consequence and likelihood weights, which reflects relative influence degree on operational risk. Finally, in order to assess the comprehensive operational risk of CTCS, cloud model is used to logically calculate quantitative results, and the CTCS-3 in Wuhan-Guangzhou high-speed railway is empirically investigated to analyze its overall operational risk level. The result shows that its risk level is between medium and low, and more inclined to low, which means being acceptable but not ideal. Meanwhile, some specific suggestions and measures are proposed to eliminate or reduce RFs with higher frequency and worse consequence.

Reliability analysis on the train control system in the CTCS-3 operating mode

Purpose This paper aims to study the reliability of the high-speed train operation control system in the Chinese Train Control System Level 3 (CTCS-3) operating mode. Design/methodology/approach Dynamic fault tree and Bayesian network method are adopted to analyze the reliability and weakness of the CTCS-3 system. Findings First, a physical architecture and data flow diagram of the CTCS-3 system are established according to the typical structure and functions of the CTCS-3 system. Second, the dynamic fault tree of the CTCS-3 system is constructed. Considering the prior probability of the bottom event and the existence of dynamic redundancy, the dynamic fault tree is transformed into a Bayesian net. The reliability of the CTCS-3 system is carried out based on the prior probability and the weakness that affects the reliability of the system based on the posterior probability is also analyzed by the Bayesian network. Finally, it is disclosed that the impact of the on-board subsystem on the reliability of the CTCS-3 system is generally greater than that of the ground subsystem. The two weakest modules in the onboard subsystem are the driver-machine interface (DMI) and balise transmission module (BTM) and the weakest one in the ground subsystem is Balise. The analysis results are generally consistent with the malfunctions in the field operation of China’s high-speed railway. Originality/value (1) By reasoning, the reliability of the train operation control system in the CTCS-3 operating mode meets the standard requirements. (2) Through backward reasoning, it is found that the failure of the onboard subsystem leads to a greater probability of failure of the train control system. (3) The DMI, BTM and automatic train protection computer unit modules are weak components in the onboard subsystem. Vital digit input&amp;output, train interface unit and train security gateway are rarely involved in previous research, the result in this paper shows that these three modules are also weak components in the subsystem, which requires attention.

Sustainable Fault Diagnosis of Imbalanced Text Mining for CTCS-3 Data Preprocessing

At present, the method for fault diagnosis and maintenance of the CTCS-3 (Chinese Train Control System Level 3) electronic equipment relies too heavily on expert knowledge. Moreover, the use of historical fault data is not valued. This paper proposes a sustainable fault diagnosis model based on imbalanced text mining. First, to process fault data from the field recorded in natural language, natural language processing technology is used to extract fault feature words. Then, a term frequency-inverse document frequency model is used to transform the fault feature words extracted from the database into vectors. It is worth noting that imbalance in the fault samples affects the accuracy of this sustainable fault diagnosis model. To solve this problem, we use the borderline-synthetic minority over-sampling technique in the step of predicting train fault components, we also use the backpropagation neural network we proposed and the naive Bayesian model which is commonly used as a classification model, to compare the prediction accuracy of these two algorithms. The experimental results perform well, which proves that the fault diagnosis method using the backpropagation neural network can further assist engineers to complete timely repair and maintenance work. The research in this paper has played a very important role in technical support for intelligent train dispatching and command, and will also play a positive role in technical support for the automatic operation of urban rail transit under the prevention and control of the new coronavirus.

Optimizing Minimum Headway Time and Its Corresponding Train Timetable for a Line on a Sparse Railway Network

In western China, railway lines are sparse, and there is a large fluctuation in transport demand under different transportation scenarios, which yields severe difficulties in setting up a signaling system and making a train timetable. To meet the fluctuating transport demand effectively and provide efficient train services in the changing multimodal transportation market, a new Chinese train control system based on flexible minimum headway time (FCTCS) is introduced and going to be implemented. Considering that the cost of implementing signaling systems corresponding to different minimum headway times varies significantly, it is necessary to find an optimal minimum headway time and design its corresponding train timetable. In this paper, we propose a mixed integer linear programming model for selecting an optimal minimum headway time, with which a satisfactory train timetable is generated with the consideration of symmetry transport demand. The objective function is to maximize the total profit of train operation. We further develop genetic algorithm with an integer and binary coding method for searching for the solution. Finally, a set of numerical tests based on a railway line in a sparse railway network in western China is used to demonstrate the validity and effectiveness of the proposed model.

Non-Deterministic Delay Behavior Testing of Chinese Train Control System Using UPPAAL-TRON

The Chinese Train Control System level 3 (CTCS-3) is an open and real-time safety-critical system. Due to the non-deterministic delay behavior in the environment, there is a large number of stimuli to the train control system with different patterns of arrival times. Control strategies must be well considered, as either the logic of the function fails or the real-time constraints are dissatisfied, may directly lead to significant human injury or financial loss. In this paper, we introduce the notion of test specification and the relativized timed input/output conformance based on timed automata theory. A new test case generation and execution algorithm has been proposed, by which the tester can reset Implementation Under Test (IUT) whenever they want, make it more sense in specific domain fields. We apply UPPAAL-TRON based online conformance testing framework to test nondeterministic delay behavior of Radio Block Center (RBC) handover scenario of CTCS-3 against critical safety, real-time, and liveness properties (defined in the system requirement specification (SRS) documents). Our experiments show that assurance of collision avoidance and train non-derailment can be guaranteed, but emergency brake intervention may happen with low probability in this scenario under the requirements specified in the SRS document.

Novel Graph-Based Train Control Data Verification Method for Chinese Train Control System

The train control data is crucial for the safe operation of trains. However, the correctness of train control data relies too much on expert experience in the field of railways due to the complex railway line situations. To address this problem, a graph theory based data model is proposed to describe the signals and track sections of critical train control route information. Then, the correctness verification theorems for route data are proposed by applying the mathematical formalism representation. Furthermore, a verification theorem is proposed to check the correctness of the single route data. In addition, another theorem is proposed for ensuring the correctness of invasion insulated track sections data. Theorems for different kinds of conflicting routes are also proposed to verify the conflict relations between routes. Finally, a case study is presented to illustrate our proposed modeling and verification method. The results show that the proposed verification method is feasible to CTCS-3, which can implement the data verification process in a formal way.

Towards A Test Paths Generation Method for CTCS Level Transition

Test case is an important basis for correctness and safety verification of Chinese Train Control System (CTCS). Focusing on the test cases generation method of UPPAAL which is widely used in CTCS testing activity, the problems are analyzed, and an improved test cases generation method for CTCS is proposed. First, the process and characteristics of UPPAAL test cases generation method are analyzed; then the test requirements of CTCS are studied, and a test cases generation method based on UPPAAL query file is proposed. Finally, taking the level transition function of CTCS as an example, test cases are generated by the proposed method, which shows that this method can meet the test requirements of CTCS.

Survey of Performance Evaluation Standardization and Research Methods on GNSS‐Based Localization for Railways

Global navigation satellite systems (GNSS) has been regarded as a key technology for train localization in the future, as GNSS-based localization can reduce the deployment of wayside equipment, and offer a high-accuracy determination in a cost effective way. However, the standardization of GNSS-based localization performance characteristics has not been done in railway. This can restrict the development of GNSS for safety related applications, which need critical requirement for the. The main objective of this paper is to provide a survey of research dealing with performance evaluation standardization. Train localization technique and performance requirement in Chinese train control system (CTCS), GNSS performance characteristics suggested in standards and guidelines, characteristics of accuracy/integrity/reliability/availability/safety for GNSS-based train localization and related evaluation approaches are presented. Some issues in GNSS-based train localization are highlighted based on the survey.

Formal Verification of AADL Models by Event-B

AADL is widely used to depict the architecture and behavior of real-time safety-critical systems such as avionics and aerospace. The development of these systems has strict requirements for building fault-free systems. Formal verification is frequently applied to verify the critical properties of the systems, such as safety and liveness; however, the formal verification is not supported by AADL. Model transformation is commonly applied to provide formal semantics; hence, the AADL model can be verified by a language that supports formal verification in addition to the ability to cover all AADL model behavior. Event-B, with its proof obligation, is increasingly used to model and verify safety-critical systems. This paper presents the transformation of the AADL model into Event-B, which captures most AADL components and behavioral actions to be effective in the verification of current real-time systems models. Then, we define theorems and invariants of safety and liveness properties to be proven by using the RODIN platform. To demonstrate the efficacy of our method, we model the AADL of movement authority (MA) control of the Chinese Train Control System, transform the AADL model to Event-B and verify its crucial properties.

Traffic Management and Energy Optimization for High-Speed Trains: An overview of methods for saving energy

The organization and management of train transportation focus on two aspects: organizing transportation and managing safe operation of trains. Many countries have created different organizational structures according to their regulatory and economic conditions, including full speed operation, passenger -cargo mixed transportation, coline-matching operational modes of different -speed trains, and so on. The train operation control system is essential for ensuring the safe maneuvering of trains. The ground and station -linking equipment realize the interlocking control function, generate the basic data as required, and transmit real-time information to the train through dedicated vehicle -ground communication equipment. After the train receives the data, the train speed control curve is generated, and the pertinent equipment is enabled to safely and efficiently operate the train. The train operation control systems currently in use include the Chinese Train Control System (CTCS), the Japanese Automatic Train Control (jATC), and the European Train Control System (ETCS), among others.

The Missing Link in the Realization of the African Integrated High-Speed Railway Network: Rules on Technical Standards and Operation

One of the major objectives of the African Union (AU) is to develop an integrated high-speed railway network connecting major African cities for improved continental trade and competition. This paper provides an overview of the main technical aspects of high-speed railway lines with special focus on cross-border operational and technical interoperability. It briefly describes the missing link in realizing a truly interoperable high-speed railway network for the African case. It introduces the technical aspects of railway lines that must be unified for cross-border operation. It also outlines the reasons that may explain the global success of the European Rail Traffic Management System (ERTMS), offering the author’s view on factors that continue to influence decision making in favor of ERTMS over other national and not interoperable solutions such as the Chinese Train Control System (CTCS). The paper concludes by suggesting the way forward for combined continental effort to realize the African Integrated High-Speed Railway Lines Network as part of the African Union’s Agenda 2063.&#x0D;

Modeling and Analysis the Effects of EMP on the Balise System

Balise system is one kind of high-rate point-mode data transmission equipment. It plays an indispensable role in Chinese Train Control System (CTCS), and it has been immigrated and widely used for passenger dedicated lines and high-speed lines. Thus, its working conditions directly affect train operation safety. However, the balise information transmission system (BITS) is based on the principle of electromagnetic induction, and the communication process is susceptible to external electromagnetic interference. Therefore, it is vital to study the influence of transient signal interference on the balise system. This paper builds the up-link model between the vehicle antena and the balise, and verifies the model’s correctness using finite-difference time-domain method and electromagnetic field theory. This paper analyzes the effect of electromagnetic pulses on the transponder's uplink and simulates the coupled current under irradiation. The spectral distribution of the three types of pulse interference is analyzed according to relevant standards. Strong electromagnetic pulses have a strong energy distribution in the working frequency band of the up-link, which will generate in-band interference and bit errors. It will affect the balise communication and threaten the safety of train operation. As we know we are the first to analyze the effects of EMP on Chinese BITS, which will lay a foundation for the research of electromagnetic anti-interference or protection to high-speed railway.

Reliability evaluation of the Chinese Train Control System Level 3 using a fuzzy approach

The Chinese Train Control System Level 3 (CTCS-3) has been developed to ensure the safe and efficient operation of high-speed railway networks in China. Failure of the CTCS-3 may result in serious accidents, causing damage to assets and risking the safety of passengers. In this paper, the reliability evaluation of the CTCS-3, comprising an onboard and trackside subsystem, is conducted using the fault tree analysis where the basic events are divided into known failure rate basic events and unknown failure rate basic events. The probabilities of the occurrence of the known basic events are obtained from field data, while those of the unknown failure rate basic events are estimated by expert judgment. The fuzzy set theory is then adopted to deal with the imprecise expert judgment. Considering a specific operational scenario, to accomplish one mission, the failure probability of the CTCS-3 is calculated. Importance analysis is carried out not only to identify the critical basic events but also to provide suggestions on the improvement of preventive maintenance. Sensitivity analysis shows that hardware factors have the most significant effect on the reliability of the CTCS-3.