Ethernet-based network with high reliability for railway signaling systems

Recently, vital devices of the railway signaling systems have been computerized in order to ensure safe train operation. Due to this computerization, we have gradually come to need networking interfaces between these devices. Thus it is important that there be reliable communication links in the signaling systems. Network technologies are applied in the real-time industrial control system, and there are numerous studies to be carried out on the computer network technology for vital control systems such as railway signaling systems. For deploying the studies, we consider costs, reliability, safety assurance technique, compatibility, and etc. In this paper, we propose the Ethernet for railway signaling systems and also precisely describe the computer network characteristics of vital railway signaling systems. Then we demonstrate the experimental results of the proposed network algorithm, which is based on switched Ethernet technology with redundancy scheme.

The development of the effective and economical protection measures is vital for the railway signaling systems because the lightning damages cause the disruption of the railway transportation systems. In general, the railway signaling systems are set up at a wayside and directly connected to the rails through cables. The lightning surges can invade the railway signaling systems via the cables and cause damages to the systems. Accordingly, clarifying the propagation characteristics of lightning surges along the rails is essential to develop the lightning protection measures in the railway signaling systems. We have carried out the field tests to examine both surge impedance and surge propagation velocity of the rails. This paper proposes a calculation model of the surge propagation characteristics along the rails. We measured the frequency‐dependent four‐terminal parameters of the rails to estimate the distributed parameter adopted in the calculation model. The results of surge impedance and surge propagation velocity calculated by the proposed model almost agree with the experimental results. Moreover, the proposed model can calculate the surge attenuation along the rails. This model is applicable to the development of lightning protection measures for the railway signaling systems. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In accordance with the development of recent computer technology, the dependency of railway signaling system on the computer software is being increased further, and accordingly, the testing for the safety and reliability of railway signaling system software became more important. This thesis suggested an automated testing tool for coding rules on this railway signaling system software, and presented its result of implementation. The testing items in the implemented tool had referred to the international standards in relation to the software for railway system and MISRA-C standards. This automated testing tool for railway signaling system can be utilized at the assessment stage for railway signaling system software also, and it is anticipated that it can be utilized usefully at the software development stage also.

The simulation of a modern railway system on the cyber range will investigate the supple behavior of cyber-attacks in a modern digital railway system. The contemporary digital railway simulation architecture will focus on the railway's signaling system and the control command system, which is a classic SCADA system. With the introduction of IoT technology to railway systems, they have become vulnerable to cyber-attacks. The simulation is conducted on the cyber range server by simulating STCS. The cyber threats will be analyzed through penetration testing using Kali Linux on the simulated STCS on the cyber range. We analyze the impact of the threat agent groups, especially denial of service (DoS) and quay chain attacks that mainly target the STCS. The DoS attack generates the congestion of packets in the railway system network and will compromise the SCADA components in the STCS. The quay chain attack compromises the SCADA component, resulting in a delay in the signal system of STCS. The attack tree analysis helps us to understand the behavior of threat agents on STCS. Based on the research, we identified some mitigation techniques to reduce the cyber-attacks impact on the modern digital railway system.

The regenerative braking of railway vehicles is widely used in DC railway systems all over the world. This mode of operation provides an opportunity to reuse part of the energy consumed by vehicles, and makes the railway system more energy efficient. During regenerative braking, not only energy management is an issue, but also Electromagnetic Compatibility EMC issues, such as interference of generated current harmonics with a railway signaling system. In this paper, the selective harmonic elimination modulation technique (SHE-PWM) was introduced to the traction drive with a three-level inverter to reduce specific catenary current harmonics generated during regenerative braking. The simulation model of a traction drive appropriate for harmonics analysis was proposed and verified by the measurements in the low-power laboratory drive system. The model was re-scaled to the 3 kV DC system for further study. The model of an induction motor with electromotive force and the method of its calculation was proposed. Furthermore, an analysis of the braking chopper operation was carried out. The asymmetric control of braking chopper was proposed to reduce the current harmonics below limits during chopper operation.

Despite significant progress in the development of microelectronic rail automatic systems observed in recent decades, relay-contact devices are still widely used in railway signalling systems, that are fundamental to the safe operation of railways and must perform predictably and reliably.Thus, signalling relays used for safety-critical or safety-related applications in railway signalling systems should be properly maintained and tested to ensure their performing safely and reliably throughout their expected service life.With the purpose of developing a method for detecting defects in movable armature of the signalling relay, the time dependences of transient currents during relays switching have been investigated for relay in various technical conditions: in operable condition, as well as with artificially created defects (bends) of contact springs. The measured data have been analyzed in the time and frequency domain using the wavelet transform modifications (CWT, DWT, DWPT).The analysis of the transient currents was carried out using segmentation of the current characteristics of the relay. The relay transient current at first and third segments which corresponded to unmovable anchor state, increase with time during relay switch-on approximately as the exponential function.The time constants of the relay current were calculated by approximating the measured current-time dependences at the first segment of the current curve by exponential function.The presence of defects in the movable armature of the relay had practically no effect on the values of calculated time constants.However, these values strongly depended on the technical condition of the relay magnetic circuit and the relay coil, as well as on the voltage applied to the coil terminals. This behavior of the relay time constant on the first segment of the relay current characteristic makes it possible to use this parameter to monitor the technical state of the electromagnetic relay system.Defects of the armature and contact springs led to the appearance of additional features at the second segment of the relay transient current, which corresponded to the movement of the armature. The magnitude of these features on the current curve depended on the value of bending of the relay's contact spring. The width and appearance time of the features at the second segment of the current-switching curve correspond to the non-simultaneous switching of the relay contacts. To determine the amplitude (energy) of these features (peaks) on transient current curve, their duration and the times of appearance, the wavelet transform was used. The results of investigations confirmed the possibility of determining the defects of the relay movable armature by using wavelet analysis of the second segment of the relay transient current characteristic.

Efficient and safe railway signalling systems, together with energy-saving infrastructures, are among the main pillars to guarantee sustainable transportation. ERTMS L3 moving block is one of the next generation railway signalling systems currently under trial deployment, with the promise of increased capacity on railway tracks, reduced costs and improved reliability. We report an experience in modelling a satellite-based ERTMS L3 moving block signalling system from the railway industry with Simulink and Uppaal and analysing the Uppaal model with Uppaal SMC. The lessons learned range from demonstrating the feasibility of applying Uppaal SMC in a moving block railway context, to the offered possibility of fine tuning communication parameters in satellite-based ERTMS L3 moving block railway signalling system models that are fundamental for the reliability of their operational behaviour.

The railway signaling system is being converted to the computer system from the exiting electrical equipment, and then the dependency on software is being increased. So far, the software validation has been mainly dependent profess, the these methodology is just depended to software experts as a tester. So it is our situation where not only validation of the document on safety activities being required, but also another automatci testing tool for vital railway signaling software. There were difficult to take advantage at the existing software black-box testing tool like usage of internal memory access of target system. This paper have proposed a new black-box testing tools with enhanced usability and the represents the design and prototype result for proposed tool.

This tutorial E-book is based on the long-standing experience of teaching railway operations and signalling at TU Braunschweig and other universities and higher vocational training institutions in different parts of the world. It explains the fundamental principles all railway signalling systems have in common. This is done in a generic way that does not focus on specific national solutions. It covers basic elements and terms, principles for safe train separation, interlocking principles, automatic train protection, and level crossing protection. It also contains a glossary with definitions of relevant terms.

Electronic information engineering is a system engineering based on computer network and other modern technologies, mainly including information collection, information processing, equipment maintenance and system construction. With the continuous development of computer network technology, electronic information engineering has also made breakthrough progress. Computer network technology is mainly used in the information transmission link, information resource sharing link and information remote control link of electronic information engineering, which brings great changes and improvement to people's daily work and life.

Among the subsystems of railway, signalling system is the most important and key equipment of the automation system. Railway signalling system is responsible for directing and used to ensure the safety of train operation, to improve the efficiency of transport and other important tasks, thus the system has an irreplaceable role and high requirements of reliability. The graphical modeling ability of Stochastic Reward Net (SRN) for system reliability analysis can make the model intuitively described, at the same time, SRN can automatically generate a continuous time Markov chain, which has strong ability in mathematics. In this paper, firstly, the function and equipment structure of the railway signalling system is carried out, and then the reliability model of the system is established based on SRN to provide a reliable basis for the design and analysis of railway signalling system.

A new fail-safe node using transputers for application in railway signaling systems is reported. This fail-safe node provides fault tolerance and safe reaction, which are required for railway signaling systems. The basic scheme of the fail-safe node is discussed, together with the concepts of leadership based on rotation, recovery in the fail-safe node, reconfiguration, and safe shutdown. >

In high-speed railway signaling systems, the network structure of the Train Control Center and Inter-locking Integrated System (TIS) is highly complex, with a large number of interfaces, numerous redundant channels, and forwarding components such as switches. These factors result in challenges such as insufficient accuracy, low efficiency, and poor real-time performance in terms of network monitoring and fault diagnosis. As the scale of railway yards continues to expand, these issues are becoming increasingly prominent. To address these challenges, this paper proposes a network fault propagation model based on the Fuzzy Broad Learning System (FBLS). By leveraging nonlinear transformations and feature mapping techniques, FBLS can efficiently extract and analyze network fault features, even with a relatively small amount of data. Experimental results show that the FBLS-based diagnostic model achieves higher accuracy and faster response speed in fault identification and propagation path analysis compared to traditional graph theory and fuzzy reasoning methods. Further comparisons with existing methods validate the advantages of FBLS in handling multi-source data, improving noise tolerance, and adapting to large-scale railway yard network systems, demonstrating its broad application prospects in railway signaling systems.

The International Union of Railway provides an annually safety report highlighting that human factor is one of the main causes of railway accidents every year. Consequently, the study of human reliability is fundamental, and it must be included within a complete reliability assessment for every railway-related system. However, currently RARA (Railway Action Reliability Assessment) is the only approach available in literature that considers human task specifically customized for railway applications. The main disadvantages of RARA are the impact of expert’s subjectivity and the difficulty of a numerical assessment for the model parameters in absence of an exhaustive error and accident database. This manuscript introduces an innovative fuzzy method for the assessment of human factor in safety-critical systems for railway applications to address the problems highlighted above. Fuzzy logic allows to simplify the assessment of the model parameters by means of linguistic variables more resemblant to human cognitive process. Moreover, it deals with uncertain and incomplete data much better than classical deterministic approach and it minimizes the subjectivity of the analyst evaluation. The output of the proposed algorithm is the result of a fuzzy interval arithmetic, $\alpha $ -cut theory and centroid defuzzification procedure. The proposed method has been applied to the human operations carried out on a railway signaling system. Four human tasks and two scenarios have been simulated to analyze the performance of the proposed algorithm. Finally, the results of the method are compared with the classical RARA procedure underline compliant results obtain with a simpler, less complex and more intuitive approach.

Railway signaling systems are vulnerable to lightning damage. Currently, countermeasures against lightning surges are not available because overvoltages occurring from lightning have not been quantitatively examined. This paper presents a method for estimating the occurrence frequency of lightning overvoltages in railroad signaling equipment. The authors describe how overvoltages and surge currents at level railroad crossing systems were measured during periods of significant lighting occurrence. Using the measurements, the authors were able to derive an equation for estimating for estimating the occurrence probability of lightning damage. The equation was then used to evaluate the rate of reduction in lightning damage against the level of protection against lightning.