Track Circuit Research Articles

A precast slab track partially reinforced with GFRP rebars

This study developed and investigated a precast slab track system partially reinforced with glass fiber reinforced polymer (GFRP) rebars in the transverse direction, which mitigated the loss of track circuit current by reducing magnetic coupling between the rails and steel reinforcements. An electric analysis was conducted and the results of the analysis verified that the GFRP rebars mitigate the reduced current strength produced by electro-magnetic induction. In the study, a threedimensional finite element method and flexural experiments were used to study the mechanical behavior of the proposed slab track.

Revisiting the 7/23 train accident using computer reconstruction simulation for causation and prevention analysis

Accident reconstruction by means of computer simulation facilitates the analysis of the causes of accidents and deriving suggestions for preventing an accident. A train movement simulation model based on cellular automata is developed in order to reconstruct the train collision process. An event-driven accident reconstruction procedure is proposed to describe the aberrant train movement processes. The selection of accelerations and decelerations is based on the statistically average tractive, resistive, and braking forces related to train movement speeds. The reconstruction results regarding the collision accident between multiple-unit trains D3115 and D301 on July 23, 2011 in China (the 7/23 accident for short) demonstrate that the proposed reconstruction methodology can achieve remarkable accuracy. The 7/23 accident reconstruction reveals that train D301 ran according to illogical track circuit code signals, indicating the disappearance of train D3115 running ahead, which is consistent with the official report. It is suggested that online analysis of train movement situations is conducive to quantitatively justifying train operation mechanisms and safety. A further finding is that the marginal emergency braking positions for preventing such an accident are only located beyond approximately 0.555 km. The lesson drawn from this accident reconstruction is that advanced automatic train control cannot paralyze the driver’s alertness, particularly in an environment of atrocious weather, which often induces failure of the train control equipment and endangers the safety of train operations.

Application of multifractal detrended fluctuation analysis in fault diagnosis for a railway track circuit

The outdoor equipment failures of track circuits are usually not easy to be detected. In addition, the location of outdoor equipment failures can cause trouble for on-site maintainers. To solve the...

Track Circuit Fault Diagnosis Method based on Least Squares Support Vector

In order to improve the troubleshooting efficiency and accuracy of the track circuit, track circuit fault diagnosis method was researched. Firstly, the least squares support vector machine was applied to design the multi-fault classifier of the track circuit, and then the measured track data as training samples was used to verify the feasibility of the methods. Finally, the results based on BP neural network fault diagnosis methods and the methods used in this paper were compared. Results shows that the track fault classifier based on least squares support vector machine can effectively achieve the five track circuit fault diagnosis with less computing time.

An Optimized Link Layer Design for Communication-Based Train Control Systems Using WLAN

With the advent of machine-to-machine and vehicular-to-everything communication systems, next-generation train control systems known as communication-based train control (CBTC) systems are also gathering increased interests both from academia and industry. Unlike the traditional train control systems based on track circuits, CBTC systems are expected to provide greater transportation capacity while ensuring safety by exploiting wireless communications between trains and wayside access points. However, due to the nature of wireless channels, packet transmission delays between APs and trains can greatly affect the train control performance. Most previous works have adopted an adaptive modulation and coding (AMC) method that minimizes the average delay to improve the control performance taking care of transmission errors due to channel fading. However, medium access control (MAC) layer contention due to multiple competing trains, which can entail significant degradations of the delay and control performance, has not been considered. Therefore, we propose an optimized link layer AMC method for CBTC systems using wireless local area network that encompasses the impacts of fading channels as well as of MAC layer contention. With much reduced required information, the proposed scheme enables to select the transmission mode that minimizes this average delay in each control period. The simulation results show that the proposed method greatly outperforms the conventional schemes over a wide range of parameters and settings.

Transient analysis on track circuits in crack state

The transient transformation of track circuit between the normal state and crack state is analyzed. Firstly, the model of crack state of track circuit in the complex frequency domain is established. According to the boundary conditions of crack state of track circuit, the expression of current traveling wave in the receiving end is obtained in complex frequency domain. Based on it, the numerical solution in the time domain is got by FFT&IFFT conjunction with quotient-difference (Q-D) algorithm. Then, the steady state of circuit in normal state is taken as state of zero moment of track circuit, the transient process from normal state transform into crack state is solved. Thirdly, the Electro-Magnetic Transient Program (EMTP) model of crack operation is established to prove that the transient analysis result is correct. It provides a power theoretical basis to distinguish the operation state of track circuit by transient analysis.

Comparative analysis of experimental and calculation methods for determination of the traction current harmonics distribution in rails

The purpose of this work is to perform the comparative analysis of experimental and calculation methods for determination of the distribution of traction current harmonics in rails. To investigate the distribution of traction current in the rails, the special marks (flags) were set up at a certain distance (100, 300 and 500 m) from the point of measurement along the track. The moments of passing the train past the flags were recorded in a computer due to a sound signal from the train, as well as visual observation. The train was moving in the measuring section in a quasi-stationary mode with an average speed of about 48 km/h. Traction current was measured in circuit of the inter-throttle jumper with using an inductive contactless sensor and registered using computer.The distribution of the return traction current harmonics in rails for AC feeding systems were modeled by using the multi-conductor transmission line (MTL) model.Some discrepancies in the results of experimental and calculation methods were observed. One of main reason of measurement errors were an inaccuracy in determining distances from the train to the measurement point. Calculation errors were related mainly with using inaccurate electrical parameters of track in model, in particular, the track ballast resistance and the ground resistances.However, in general, the considered model can be used for investigation of the traction current harmonic propagation in rails from train, and their influence on the track circuits receivers for different cases including the variation of the track circuits electrical parameters, as well as the number of rolling stock units in the feeder zone. Such analysis of harmonic in rails is important for revealing the causes of failures in railway signalling system operation under simultaneous affecting on it several factors adverse to safe operation.

ВЫБОР АНАЛИЗИРУЮЩЕЙ ВЕЙВЛЕТ-ФУНКЦИИ ДЛЯ ЗАДАЧИ ДИАГНОСТИРОВАНИЯ АППАРАТУРЫ ТОНАЛЬНЫХ РЕЛЬСОВЫХ ЦЕПЕЙ

ВЫБОР АНАЛИЗИРУЮЩЕЙ ВЕЙВЛЕТ-ФУНКЦИИ ДЛЯ ЗАДАЧИ ДИАГНОСТИРОВАНИЯ АППАРАТУРЫ ТОНАЛЬНЫХ РЕЛЬСОВЫХ ЦЕПЕЙ

Машинная классификация режима работы электрической рельсовой цепи на основе логистической регрессии

Машинная классификация режима работы электрической рельсовой цепи на основе логистической регрессии

A Study for the Condition Based Maintenance of the Track Circuit applying Machine Learning

A Study for the Condition Based Maintenance of the Track Circuit applying Machine Learning

Машинная классификация режима работы электрической рельсовой цепи методом опорных векторов

Машинная классификация режима работы электрической рельсовой цепи методом опорных векторов

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).

Comparative Analysis of Means Detectors in Surabaya - Madiun Cross

One example of technological developments in signaling systems in Indonesia is the use of detection facilities on rail lines. A detector is a device that functions to detect the presence or absence of train facilities on the railroad track. Detection equipment is divided into two types, namely axle counter and track circuit. Track circuit detects the presence of trains on the rails, while the axle counter functions to count train axles. This study aims to find a detection system for facilities that is suitable and in accordance with the conditions of the Surabaya-Madiun cross and find out the characteristics for the installation of detection facilities in accordance with the pathway. To find out the appropriate facility system, the two tools are analyzed in terms of system reliability, environmental influences, advantages and disadvantages, disruptions, maintenance, and operations. The results showed that an effective and efficient way of detecting traffic in Surabaya - Madiun was the detection of a double head axle counter facility. This tool is very suitable to be installed in the emplacement.

Fast approach to calculate the ballastless track impedance

PurposeThe track impedance is one of the most important parameters in designing the track circuit which is widely used in the railway signal control system to detect the presence of a train. This paper aims to calculate the ballastless track impedance by taking account of the influence of reinforcement bars.Design/methodology/approachThis paper proposes a two-step decomposition approach to calculate the ballastless track impedance. The basic idea is evaluating the track impedance without the reinforcement bars by using two-dimensional (2D) finite element method (FEM), and the incremental impedance, because of the reinforcement bar, is calculated by the partial element equivalent circuit (PEEC) method.FindingsThe numerical examples show that the proposed approach can guarantee the accuracy and largely reduce the computing time, at least 20 times, compared with the direct three-dimensional (3D) FEM method.Research limitations/implicationsThe study provides a fast approach to calculate the ballastless track impedance. However, compared with the 3D FEM method, the results are less accurate because of the approximation and assumption adopted in the method. A future study should pay more attention to improve accuracy of the model.Originality/valueA fast approach is proposed to calculate the ballastless track impedance taking account of the influence of the reinforcement bars. The computing time can be largely reduced by using the method. With the proposed approach, the influence of insulation of the reinforcement bars on track impedance can be analyzed.

Особенности системы управления движением поездов на высокоскоростной магистрали «Москва–Казань–Екатеринбург»

Objective: To consider the requirements for the train control system (SUDP) at “Moscow-Kazan-Yekaterinburg” high-speed network (VSM). To develop system-wide requirements for SUDP, including the selection of the structure and composition of subsystems. Methods: Computer-based interlocking with contactless control of vehicles should be applied at the stations as the main means for train traffic control. Vocal frequency track circuits were determined as the major means for free and busy status control of track at stations and blocks, an information channel giving an update of a track ahead, and the means for a rail integrity test. Stationary equipment for train collision avoidance via radio channel is to provide train traffic with speeds up to 400 km/h, multiple-aspect ALS-YEN (integrated continuous automatic cab signaling system), depending on control technology with speeds up to 250 km/h and ALS (automatic locomotive signaling system) – up to 160 km/h. Results: The issues of providing reliable and safe functioning of SUDP were considered, as well as liveness and interoperability. Practical importance: Control system realization in the suggested configuration with combined data communication via radio channel and conventional ALS and ALS-YEN facilities will make it possible to provide train traffic collision avoidance backup, as well as interoperability with high-speed transport lines. Keywords: High-speed network, train control system, centralized traffic control, computer- based interlocking, train traffic collision avoidance, radio-block center.

Combination of SHE- and SHM-PWM Techniques for VSI DC-Link Current Harmonics Control in Railway Applications

The paper presents an innovative concept of applying a combination of well-known selective harmonic elimination (SHE) and selective harmonics mitigation (SHM) methods to shape a spectrum of catenary current harmonics, generated by a traction drive system equipped with a voltage source inverter. Application of this method allows for reducing distorting influence of a modern rolling stock supplied by a 3 kV dc catenary on the railway signaling, command, and control systems. The efficiency of the proposed method is independent of synchronization of a vehicle's inverters and of load balance of traction motors, which makes it more reliable than as it is proposed in the literature. Results of computer simulations were presented and compared with laboratory measurements. The obtained dc-link current spectrum using the proposed SHE/SHM method was compared with spectra received using synchronized and unsynchronized sinusoidal pulse-width modulations (SPWMs). Based on the conducted tests, it was shown that the proposed method of control, which was implemented in a laboratory drive system, is effective in reducing dc side current harmonics in a frequency range of 1300–3100 Hz, which is used by track circuits on railway lines, e.g., in Poland. The technique proposed by the authors allows taking into account any restrictions arising from the technical nature of low-frequency traction drives.

Analysis of disturbing effect of 3 kV DC supplied traction vehicles equipped with two-level and three-level VSI on railway signalling track circuits

Abstract Electric traction vehicles cooperating with a 3kV DC traction system and equipped with drive systems based on voltage source inverters are the most significant sources of disturbances for a railway signalling system. Every traction vehicle to be authorised for operation on railway lines must fulfil the limits imposed on current harmonics magnitudes and those provided by railway operators. The solution introduced for prototypes of most modern traction drives is to replace the two-level inverters with three-level topology. Therefore, it is essential to establish the influence of the new solution on the railway signalling system. This paper presents a comparative analysis between simulation results delivered for two and three-level traction drive system regarding generation of disturbing current harmonics. Two types of VSI modulation techniques were taken under consideration: sinusoidal PWM (SPWM) and a new one, proposed by the authors, based on selective harmonic elimination (SHE). Furthermore, the authors presented application of one of the SHE based optimization techniques for shaping the EMU’s (electric multiple unit) DC side input current harmonics spectrum in order to meet the required limits. The described technique is based on off-line generation of a set of solutions for each of the VSI operating points and selection of the best solution for the assumed criteria. The applied simulation models and the concept of SHE control were verified in a laboratory by means of a low-power drive stand. Using the three-level inverter in traction drives system results in less current harmonics than using two-level topology without modification of the modulation technique. Thus, it does not guarantee fulfilling all limits assumed in this paper. The proposed modulation technique allows for fulfilling the limits, and the technical implementation of the proposed technique in a traction drive system will be considered in future studies.

POTENTIALS RAILWISE PROPAGATION STUDY

Purpose. To conduct the study of the potentials and currents propagation along the rails to evaluate the potential difference and the current asymmetry in the rails that may have an impact on the work of railway automatics and supervisory systems. Methodology. To compass the purpose, the author applies methods of analysis and synthesis of track circuit electrical engineering calculations, mathematical modeling and methods of homogeneous and heterogeneous ladder circuits. Findings. TheconductedtheoreticalstudiesindicatethatinthemountainoussectionsofDCtractionrailwaysthereareveryhigh-levelcurrents,wherebyevenatnominalasymmetryratio theasymmetrycurrentwill beunacceptablyhigh.The re-equipment of running line with the automatic blocking system with tonal rail circuits resulted in reduction of the number of impedance bonds, the equalizing functions of which required further advanced research, that allowed obtaining the potential railwise propagation curves when installing the impedance bonds every 6 and 5 km. The resulting potential difference was too high for railway automation systems, so the potential propagation study was conducted with impedance bonds placed every 3 and 3.5 km, which greatly improved the operation conditions of track circuits. Originality.The proposed method for calculating the propagation of potentials and currents in the rail network of DC traction line is characterized by the representation of the common ladder circuit of each rail as a series of T-shaped four-poles connected in cascade, taking into account the grounding of the contact-line supports on the nearer rail. It has allowed estimating the levels of asymmetry currents that branch into the equipment of track circuits and have a negative impact on their operation. Practicalvalue. The obtained results can be used in designing and re-equipping the running lines with new railway automatics and supervisory systems, as well as for evaluating the influence of high asymmetry currents on the railway automation systems operation.

The Algorithm Research of Blind Source Separation Based on Spatial Time-frequency Distribution for FSK Signal

Track circuit is an important guarantees of the railway security, a large number of non-stationary interference and noise induce from the electrified railway block in the process of the FSK signal transmission in the track circuit, seriously affect its testing accuracy and reliability. Aiming at the problem, this paper propose a algorithm of blind source separation (BSS) based on the spatial time-frequency distribution (STFD) and singular value decomposition(SVD). First using SVD on mixed signal to remove noise, then reassign spectrum and pre-white in STFD domain, improve the selection function of single autoterm in STFD matrix, the get unitary matrix by joint diagonal, last estimated out the mixed matrix. The algorithm is not limited with Gaussian source signal, so it has strong applicability. Computer simulation results indicate that the algorithm to effectively separate the non-stationary signals and improve its BSS performance in a low signal-to-noise (SNR) environment.

Analysis of Tracked Vehicle Vibration Response Considering the Track Circuit Vibration

To accurately describe the vehicle vibration, the vibration response of the vehicle operation system affected by the track was studied. Through the analysis of the topological structure of vehicle operation system, the flexible track model and the rigid track model was built up. The track circuit model was established by simplifying the rigid track, and its inherent vibration was calculated by eigenvalue analysis. Power spectrum method was used to compare the dynamic model of flexible track and the dynamic model of rigid track and verify the effect of track on the vibration of vehicle. The results show that the effect of track on the vibration of vehicle mainly include the inherent vibration of track circuit and the high frequency vibration related to track pitch; the computing result provides a reference basis for describing the effect of track quantitatively.