Track Circuit Research Articles

Mathematical model of the sensor for controling the condition of the track section with an adaptive receiver at the free condition of the controlled section

One of the promising areas of improvement of sensors for monitoring the condition of track sections is the development of controlling sensors, which are less dependent on changes in ballast resistance, longitudinal asymmetry and standard value of shunt sensitivity, such a direction is the development of adaptive track circuits [1-5]. The article proposes a control sensor with an adaptive receiver, principle of operation of which is that monitoring the state of the track section depends on the parameters of adjacent monitoring sensors, included in the common controlled zone CZ.Mathematical model and analytical expressions have been developed taking into account the resistance of the rails and the resistance of the insulation being carried out [6]. Proposed the coefficients of a rail fourpole with one of the choke-transformer, powered with one side. The calculated expressions of the fourpole and the criteria for the sensitivity of the rail circuit when one line is broken are presented and derived, and also the minimum transmission resistance [6].

Analysing an autonomous tramway positioning system with the Uppaal Statistical Model Checker

Abstract The substitution of traditional occupancy detecting sensors with an Autonomous Positioning System (APS) is a promising solution to contain costs and improve performance of current tramway signalling systems. APS is an onboard system using satellite positioning and other inertial platforms to autonomously estimate the position of the tram with the needed levels of uncertainty and protection. However, autonomous positioning introduces, even in absence of faults, a quantitative uncertainty with respect to traditional sensors. This paper investigates this issue in the context of an industrial project: a model of the envisaged solution is proposed, and it is analysed using Uppaal Statistical Model Checker. A novel model-driven hazard analysis approach to the exploration of emerging hazards is proposed. The analysis emphasises how the virtualisation of legacy track circuits and on-board satellite positioning equipment may give rise to new hazards, not present in the traditional system.

Field test and numerical analysis of Insulated rail joints in heavy-haul railway

Insulated rail joints (IRJs) are widely used in heavy-haul lines, owing to they are safety critical components of track circuit. However, the IRJs breaks the continuity of the rail, making rail more vulnerable to damage under the long-term wheel-rail interaction. In order to study the performance of IRJs, field investigation and tests were carried out at new IRJ and damaged IRJ. At the same time, a 3D coupling model of heavy haul train-IRJ was established for the further analysis. The result shows that in regards to rail-surface regularity, the new IRJ and the damaged IRJ exhibits convex joint and concave joint respectively. IRJs will gradually turn to concave and dipped in the vicinity of end-post under long-term wheel-rail impact. Since there is a vertical rail displacement difference on both sides of the end-post between the two IRJs, causing the wheel-rail interaction has two different impact modes, of which one is downward height difference impact and the other is upward height difference impact. In normal speed, the impact caused by the damaged IRJ is larger than the new IRJ does and it leads to a severer damage to the whole track. The displacement of sleeper at the damaged IRJ is 7.6 times larger than at the new IRJ due to the void between the sleeper and the ballast. The transfer function of displacement from rail to sleeper at the new IRJ is between 0 and 0.4, while the damaged IRJ is between 0.42 and 6.1. The transfer function can be used as a vital index to evaluate the IRJ service state. With the increase of speed, the displacement of rail and sleeper at the two IRJs increases correspondingly. For the sake of decreasing the occurrence of fatigue damage and plastic deformation of rail and plate as much as possible, the maximum depth of concave should be reined within 0.55 mm.

Design of a General Monitoring Host Machine for Railway Trackside Equipment

A large number of infrastructure and equipment are distributed along the railway, which will directly affect the safety and efficiency of railway transportation. In this paper, a general monitoring host machine for railway trackside equipment is designed to realize the power supply, automatic networking, logic operation centralized management, data collection, storage and processing of trackside equipment monitoring. The host machine consists of a CPU board, a interface board, a power board, several PLC (Power Line Carrier) communication boards and isolation transformers. It supports a variety of monitoring applications, and covers almost all monitoring requirements of trackside equipment. Based on the monitoring host machine, a monitoring system for trackside equipment of track circuit system is developed.

Методы приема и синхронизации сигналов автоматической локомотивной сигнализации

The article discusses the problems of existing methods of receiving automatic cab signalling on railway transport, an original method of receiving and processing data is proposed. The need to solve the problems is due to the requirement of a qualitative improvement in the reliability of receiving codes, and as a consequence, the capacity of existing lines. First of all, this refers to a significant increase in the quality of reception and processing of information flows from rail lines. Today it is difficult to imagine the organization of the movement of rolling stock without relying on automatic block systems with secondary sealing of tonal track circuits by frequency modulation signals or automatic cab signaling without the use of multivalued automatic cab signaling with phase-difference modulation. Taking into account the objective fact of noise emission from the operation of energy-intensive railway equipment and modern locomotives, the issues of reliability and noise immunity of receiving discrete information (including signals of traditional automatic cab signaling) are becoming more and more urgent. Analysis of the reasons for the decrease in the reliability and noise immunity of railway automation and telemechanics systems, and, consequently, traffic safety also comes to the fore.

Влияние геоиндуцированных токов на дроссель-трансформаторы рельсовых цепей железнодорожной автоматики

Objective: To consider the possibility of DC magnetization of the core of the impedance bond with secondary winding when using AC electric traction. To determine the possible influence of solar activity, and in particular the geoinduced currents, on the signaling arrangements (SAs). Methods: Analysis of the conditions and causes of magnetization of the core of the impedance bond with a secondary winding, which is the reason for a decrease in its inductance and a change in the track circuit coefficient of transmission. Description of the influence of geoinduced currents on the operation of traction substation power transformers and the using this scenario for modeling the operation of impedance bonds with secondary windings. Results: The conditions and reasons for the incorrect operation of the impedance bonds with secondary windings associated with the magnetization of the core by direct current, when using electric traction with alternating currents, have been stated; the possibility of saturation of the magnetic system of the impedance bond with geoinduced current has been analyzed; the possible consequences of the transition of the impedance bond to the saturation mode have been determined. Practical importance: The study findings broaden the knowledge about the possible influence of solar activity on the railway infrastructure facilities, which in its turn is necessary for the development of methods and means aimed at ensuring the uninterrupted operation of railway transport.

The Application of a Safety Comparator in the Track Circuit of a Railway Signaling System for Counting Overvoltage

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

A Rail line model with distributed parameters of track circuit

Models of continuous jointlesstrack circuits with an adaptive receiver are presented, where the power supply is connected to the beginning or middle of the rail circuit, and also to the locomotive receiver. The aim of the work is to develop models of rail lines, which take into account the actual current distribution along the track line and which may be used to research adaptive jointlesstrack circuits. The electric schemes of the jointlesstrack circuits are given, equations, connecting currents and voltages at the ends of the rail line, coefficient of four-pole rail lines, algorithms for calculating track circuits. In conclusion, that the track circuit can operate at an insulation resistance four times lower than the permissible value, where the permissible insulation resistance is Ri = 1om*km. New approaches and tools for analyzing and synthesizing solutions are considered, with considering account real operating conditions and disturbing factors.

Mathematical processing of the signal in the track circuit for determining the location of the rolling stock

The article considers the issues of determining the location of rolling stock on the section of the railway track. Application of mathematical apparatus of conformal mappings is proposed and justified. Principle of conformal transformations of track circuit signal into the coordinate of place of superposition of the shunt is disclosed. Visualization of conformal transformations is presented using the example of a 420 Hz track circuit. The rules for determining the coordinate of the place of superposition of the shunt is well-phrased. Factors affecting the accuracy of determining the location of rolling stock on the section of the railway track have been determined.

Optimization Design of Rail Station Signal Monitoring System Based on Role Autonomous Decentralized System

Online-expansion, online maintenance and fault tolerance are vital functions of rail signal monitoring system, which can guarantee the system always in working status and satisfy the sustainable development of rail transit. Due to the limitations of traditional centralized system structure, it is necessary to optimize the design of rail station signal monitoring system to make the system possess these functions. In this research, the novel concept of Role on Autonomous Decentralized System (RoADS) is adopted to optimize the design of rail signal monitoring system. On the one hand, RoADS has the characteristic of role dynamic conversion which is essential to realize the special function of online-expansion, online maintenance and fault tolerance. On the other hand, RoADS also can support the basic function of data collection. In order to verify the validity of the proposed method, a case study has been performed on ZPW-2000 track circuit monitoring system which is the subsystem of rail signal system mainly responsible to monitor the track circuit. The results clearly indicate that the optimized system based on RoADS can not only realize the function of data collection, but also possess the function of online-expansion, online maintenance and fault tolerance. Consequently, the proposed method based on RoADS can improve the safety level of rail transit and reduce the cost operation which is of great significance for maintaining the sustainable urban development of rail transit.

Research on protection of tuning area equipment disconnection in the ZPW-2000A track circuit

To overcome the problem of tuning area faults influencing the normal operation of the ZPW-2000A track circuit, protector models are established to protect the track circuit from interference. First, the parameters of the protector models are calculated according to the circuit resonance principle. Second, a four-terminal network model of the track circuit in a normal state is established according to transmission-line theory and the transmission equations are derived. Third, the rail voltage is simulated, and an experimental platform is built to verify the models. Finally, the transmission equations of the protectors are derived, and the variation of the rail voltage is analyzed. The results indicate that tuning area faults have significant influence on the rail voltage. However, the installation of protectors can effectively reduce the influence, and not bear on the normal operation and maintenance of the track circuit, which significantly improves the protection ability of the track circuit against tuning area faults.

Research on ZPW-2000R Track Circuit Fault Diagnosis Based on Neural Network

In view of the situation that the fault monitoring is not timely and the accuracy of fault diagnosis is low due to only indoor monitoring equipment but not outdoor monitoring equipment, an intelligent diagnosis method based on neural network is proposed. Firstly, according to the different operating environment and influencing factors of the track circuit, the method of orthogonal test is designed to obtain the information of each component There are three kinds of track circuit monitoring variables with complex environmental factors, and then the track circuit fault types are divided into three categories: sending channel fault, receiving channel fault and track fault. On the basis of rapid location of track circuit fault location, 21 kinds of specific fault types are distinguished. The simulation results show that: when using this method for track circuit fault diagnosis, even without outdoor monitoring data, it can quickly locate the location of the fault, and the location accuracy can be up to 100%. When identifying 21 fault types, the accuracy of fault diagnosis can still be up to 90%, the diagnosis rate is high and the judgment is fast, which can assist the field maintenance personnel judge faults accurately and quickly.

Design of railway signaling system using IR sensor as train detection

In this research would try to give contribution for researchers or academics about simulation of the railway signaling system. The model of railway system was built using miniature of track and train model. Small LED was used as a lamp signal. Point machine was moved by servo motor controlled by Arduino Nano. The last, track circuit was replaced by proximity sensor using IR transceiver. The result showed that the simulation could do some basic task which is occurred in railway signaling system. The design of system was created by FSM (Finite State Machine) method which would be implemented in PLC (Programmable Logic Controller). It consists of state diagram, declaration of inputs and outputs, generated logic equation, and finally is the written code in ladder logic diagram. Set route test also has been tried successfully and the lamp signal showed the color aspect correctly.

Blockchain‐enabled secure crowdsensing for trackside infrastructure information collection and validation in railway signalling data preparation

Rail operators around the world are adopting advanced control systems for railway signalling and train protection to improve their safety performance. In these re‐signalling projects, the information about the already installed signals, point machines, track circuits etc. along the trackside infrastructure is essential for the configuration of advanced signalling equipment. The conventional information collection method which is based on unmanned aerial vehicles, helicopters etc. has the access limitations in terrains such as tunnels, hilly regions, river bridges, dense forests etc. To overcome these challenges, this paper proposes the railway vehicular crowdsensing method in which one group of trains participates in this information collection and another group of trains confirms the validity of the collected information. For information exchange between the trains and centralized server, this study chooses the permissioned blockchain‐based information transaction mechanism to ensure the trustworthiness. Furthermore, the railway markup language‐based blockchain databases are included for information immutability, crowd information integration, and the automatic execution of data preparation signalling rules. Finally, the case studies are carried out to analyse the adequacy of the proposed combination of crowdsensing based secure trackside infrastructure information collection and validation, permissioned blockchain‐enabled information transaction and blockchain databases in the proposed signalling data preparation process.

Regeneration of Track Circuit and Proposal for a New Signal Control System

Regeneration of Track Circuit and Proposal for a New Signal Control System

Evaluation of the Electromagnetic Effect of Traction Rolling Stock on Track Circuits

The regulations regarding railways currently in force in Bulgaria require that each new type of locomotive, to get access to railway infrastructure, must undergo a procedure for checking its electromagnetic effect on functioning of track circuits.The relevant testing was carried out for seven types of AC and DC track circuits and for six types of locomotives intended to be put into operation (five electric locomotives and a diesel locomotive).Schematic diagrams of testing conditions are presented. During the tests the voltage waveform, frequency, and level rates at the terminals of the track receiver (on the track relay coil) were recorded for a free (normal (common) mode) and occupied (shunt mode) track circuit during the action of return traction current of electric locomotives, as well as during the action of impacts caused by operation of electrical equipment located in the body and under the frame of the diesel locomotive.For electric locomotives, the tests were carried out during the shunting of track circuits (of a tested one and of the track circuit adjacent to it), starting from the rest, lowering and raising pantographs. For a diesel locomotive, tests were carried out in a stationary mode, when inner wheelsets shunted the insulating joints of two adjacent track circuits and for different cases of arrangement of the equipment of the relay and receiver ends. During the tests, the state of the armature and contacts of track relays was monitored. The amplitude of the recorded interference was compared with voltage of reliable switching off/ on of track relays/track receivers. It was found that during the shunt mode, the recorded residual voltage in the track receiver under the action of the electric locomotive was 50 or more times lower than the reliable operate voltage and 33 or more times lower than the reliable drop-out voltage of the receiver. For a diesel locomotive, the results turned out to be similar, except for the case of shorter DC track circuits, where the amplitude of the interference was higher, but without a dangerous effect on the shunt mode.Based on the results of the tests, it was established that all types of track circuits used on the railways of Bulgaria are resistant to electromagnetic interference emanating from tested samples of traction rolling stock.

Application of OFDM transmission method for railway signalling system via track circuit

At present, railway signalling systems in which control information is transmitted via track circuits (rails) have been deployed in many applications, such as automatic train control (ATC) systems in Japan. In these systems, it is difficult to increase the transmission speed due to the transmission characteristics of rails. To overcome this problem, we have proposed a new transmission method using orthogonal frequency division multiplexing (OFDM) and evaluated a configuration in which data judgment using majority decision was applied for improving the bit error rate (BER) characteristics. In this paper, we describe an FPGA implementation of our proposed method and the performance of the implemented devices.

Impact of rail impedance intrinsic variability on railway system operation, EMC and safety

Running rails in electrified transportation systems are the interface element for several phenomena related to system performance, electromagnetic compatibility and safety: useful voltage at rolling stock, short circuit current, induced voltage, stray current, and track circuit operation. This work presents the physical and mathematical groundings of rail electrical parameters (dc and ac resistance, ac internal and external inductance) and experimental results available in the literature, discussing variability and reliability for each interface. The results consist thus of the identification of the relevant rails longitudinal electrical parameters, the presentation of a set of reliable experimental values, and the discussion of the best approach to manage their variability and uncertainty.

Modeling Geomagnetic Interference on Railway Signaling Track Circuits

AbstractMisoperation of railway signaling during geomagnetic disturbances has occurred in a number of countries. Railway signals are activated by track circuits that detect the presence of a train in a particular rail section, but geomagnetically induced electric fields can interfere with the track circuit operation, causing the wrong signal to be displayed. This paper develops a new model for track circuit operation that includes the induced geoelectric fields produced by geomagnetic field variations. Rails are modeled as transmission lines with series impedance given by the rail resistance and parallel admittance determined by the current leakage from the rail through the ballast to ground. The transmission line model is then converted into an equivalent‐pi circuit for each rail and these are combined with the track circuit power and relay components to form a nodal admittance network for the track circuit. This is used to examine the effect of induced geoelectric fields on track circuit operation. First, an individual track circuit is examined and it is shown how the length, between insulating rail joints, of the individual rails influences the geomagnetic interference voltage produced across the track circuit relay. Then a series of track circuits is considered: A general solution is developed and then the conditions are identified that allow this to be reduced to a simpler solution considering each track circuit individually. This modeling provides insight into the conditions that produce signaling problems and provides the tools to assess the geomagnetic hazard to railway signaling.

Trends in Improving Sensors for Controlling the Condition of Track Sections

Various principles can be used to implement intelligent track circuits: voltage regulation of the power supply, compensation methods for switching on rail lines and track circuit devices, receiver sensitivity adjustment, comparison of two electrical parameters of one, two, or more track circuits, as well as a combination of these methods. At present, such improvement of track circuits is becoming relevant, which would make it possible to exclude from the circuits one of the most unreliable elements - an insulating joint, use a modern microprocessor element base in devices for monitoring the state of track sections, thus ensure their reliable operation. This will significantly reduce the costs of building and operating interval control systems and increase train traffic safety. These requirements are met by intelligent track circuits, which consider the current value of the insulation resistance, the rate of change of this resistance, and the longitudinal asymmetry.