Railway Field Research Articles

Electrical capturing system for train supplying and involving parameters

Electric trains are powered by a current distribution device which depends on several parameters. The research works presented in this paper are located upstream of two types of important applications in the railway field: the electrical supply of trains involving the sliding or stationary pantograph/catenary contact and the famous problem of shunting of trains involving the wheel/rail rolling contact. These cannot be assumed without energy loss. In the case of train navigation, electric current can be transmitted by spots established between sources and the carbon strip. The quality of the pantograph/catenary contact obeys very strict specifications to ensure its maintenance, for permanent current connection. However mechanical aging of the contact and/or infrastructures, alteration of electrical contacts due to electrical arcing, the wear of collection strips during sliding, aging of the materials, are limiting effect for current flow. In this paper we will explicitly describe all the elements necessary to supply trains with electric current.

Functionality Analysis of Derailment Containment Provisions through Full-Scale Testing—I: Collision Load and Change in the Center of Gravity

In order to reduce the large damage caused by train derailment, protective facilities of various shapes and conditions can be installed on railroad tracks. These protective facilities are referred to as derailment containment provisions (DCPs) and three different types are used worldwide. However, there are no clear standards for DCP design such as installation location, size, and design load, and the performance verification of DCPs installed in the actual railway field is not sufficiently performed. In this paper, the functionality of DCP type I was analyzed experimentally. A method for estimating the collision (impact) load acting on the DCP was proposed. In addition, the containment effect of DCP type I according to the change in the vehicle’s center of gravity was identified through a comparative analysis of the dynamic motion such as roll, pitch, and yaw.

Prediction of the Remaining Useful Life of a Switch Machine, Based on Multi-Source Data

Aimed at the shortcomings of a single feature to characterize the health status and accurately predict the remaining life span of the equipment, a prediction method for a switch machine, based on the weighted Mahalanobis distance (WDMD), is proposed. The method consists of two parts: the construction of a health indicator, based on the weighted Markov distance and the prediction of the remaining useful life, based on the hidden Markov model (HMM). Firstly, a kernel principal component analysis (KPCA) is used to extract the characteristics of the power curve data of the switch machine, and the characteristics with a high correlation with the degradation process are screened, according to the trend indicators. Secondly, the resulting features are combined with multi-source information, as the input, and a comprehensive health indicator (HI) is constructed by the weighted fusion of the WDMD algorithm, to characterize the degradation process of the switch machine. The degradation model of this HI is established and trained by the HMM, so as to predict the remaining life span of the equipment. Finally, the actual operation data of the railway field is selected to verify the prediction method proposed in the paper. The results show that the state recognition and the life prediction accuracy of the proposed method is higher, which can provide effective opinions for the predictive maintenance of the switch machine equipment.

Energy Metering Data Estimation and Validation in Railways

The opening up of the railway to competition in Europe has been accompanied by many technical challenges never before seen in the railway field. One of these challenges concerns precise energy metering. As European railways have been a monopoly until now, the current systems can only measure the energy consumption of a single operator. In accordance with European law, the installation of an energy meter has been mandatory in new or refurbished rolling stocks since 2014. Nevertheless, these energy meters are still not fully reliable, with misreadings and missing readings being common occurrences. To address the problem of energy metering data reliability, this paper presents a method for validating the reading measurement based on a physical model and validates it in two different case studies. For the issue of energy metering data availability, different estimators are developed, and their performance are shown with the aim of calculating the missing consumptions for both case studies. Finally, the paper suggests how these methods may be implemented in other types of trains.

<b>Trend on Research and Development Activities Relating to Signalling and Telecommunication Systems in Railway Fields</b>

<b>Trend on Research and Development Activities Relating to Signalling and Telecommunication Systems in Railway Fields</b>

Evolyuciya germanskogo podhoda k upravleniyu gosudarstvennymi predpriyatiyami v konce XIX — pervoj polovine XX v.

The article deals with the emergency and development of German state-owned enterprises in 1871-1945. The authors consider the ways and methods of managing state-owned companies in the field of postal service, railways, gas and electricity supply, as well as forms of entrepreneurship that were created by the leadership of Nazi Germany to serve the needs of the state in preparation for World War II. The results of the study demonstrate that at the end of the 19th - first half of the 20th century the management of German enterprises in key industries was centralized by the government, both by the means of nationalizing the companies and acquiring the assets from private owners, as well as by establishing new state-owned companies.

Recent Progress on Regulating Strategies for the Strengthening and Toughening of High-Strength Aluminum Alloys.

Due to their high strength, high toughness, and corrosion resistance, high-strength aluminum alloys have attracted great scientific and technological attention in the fields of aerospace, navigation, high-speed railways, and automobiles. However, the fracture toughness and impact toughness of high-strength aluminum alloys decrease when their strength increases. In order to solve the above contradiction, there are currently three main control strategies: adjusting the alloying elements, developing new heat treatment processes, and using different deformation methods. This paper first analyzes the existing problems in the preparation of high-strength aluminum alloys, summarizes the strengthening and toughening mechanisms in high-strength aluminum alloys, and analyzes the feasibility of matching high-strength aluminum alloys in strength and toughness. Then, this paper summarizes the research progress towards adjusting the technology of high-strength aluminum alloys based on theoretical analysis and experimental verification, including the adjustment of process parameters and the resulting mechanical properties, as well as new ideas for research on high-strength aluminum alloys. Finally, the main unsolved problems, challenges, and future research directions for the strengthening and toughening of high-strength aluminum alloys are systematically emphasized. It is expected that this work could provide feasible new ideas for the development of high-strength and high-toughness aluminum alloys with high reliability and long service life.

Research on EMC Optimization of Wireless Electric Field Sensor for Rail Vehicle

In order to improve the electromagnetic compatibility of railway vehicle wireless electric field sensor, a research on electromagnetic compatibility optimization of railway vehicle wireless electric field sensor is proposed. The results show that the optimized RF radiation energy is greatly reduced from 60 to 20, which is completely lower than the standard limit of radiation disturbance, and meets the requirements of EMC design of electronic products. The feasibility and effectiveness of the optimal design are proved. The experimental results show that the test results meet the requirements of general technical conditions of electromagnetic compatibility of speed sensor, which indicates that the electromagnetic compatibility design proposed can be popularized and applied.

鉄道各所へのウルトラファインバブル水の応用

In the present study, two experimental examples as the applications by ultrafine bubble for railway fields are introduced. The first one was confirmed the cleaning effects of ultrafine bubble water on the brush cleaning machine used in the station buildings. It was found that the removal rate was increased by using ultrafine bubble in the brush cleaning machine compared to the tap water. However, it was also shown that the removal rate increased or decreased with respect to the number of rotations of the brush and the pressing force, and there were some conditions in which the effect of the ultrafine bubble could not be confirmed. In this experiment, it was shown that unevenness on the floor surface and dirt, and microbubbles grew from ultrafine bubble may be important for cleaning effect and understand of the mechanism. The second one was shown an interesting effect that the friction reduction effect by microcloth with ultrafine bubble water. In this experiment, the static frictional coefficient and dynamic frictional coefficient of the microcloth with tap water and ultrafine bubble water were measured on the glass plate. As the results, it was found that both frictional coefficients were decreased by ultrafine bubbles but when the glass plate was not dirty, both frictional coefficients did not decrease.

Fatigue crack growth rate dependency on cold expansion degree in railway steel

The increase of railway track occupancy due to high speed trains introduction in the morning and cross-border transportation of hazardous and non-hazardous materials during late hours, require particular attention for the fatigue design as well as the maintenance planning of railway superstructures. For this purpose, strategies finalized to increase the fatigue strength of railway structural parts assume great interest for railway engineers. Cold expansion technique, for example, is less expensive than other mechanical and thermal treatments, but in the literature there are no data concerning its use in the railway field, being almost all available studies focused on aluminum parts. In this paper, fatigue crack growth response of drilled specimens extracted from rails submitted or not to cold expansion are presented. Two degree of cold-expansion, 2% and 4%, are investigated in terms of fatigue crack growth rate, and the results compared to those obtained with not-expanded specimens. It is found that cold expansion postpones fatigue crack initiation, and that this effect is more pronounced for increasing degree of cold expansion. A preliminary predictive model was developed, based on the sum of the Stress Intensity Factors calculated with the weight functions and concerning the residual stress field induced by cold expansion, and the one generated by the external loads.

ANALYSIS OF FACTORS CAUSING JABODETABEK COMMUTER TRAIN DELAY

The goal to be achieved through this research is to identify the factors that cause delays in the commuter train journey across Bogor-Manggarai Jakarta. The research question is why there is a delay in the journey of the Jakarta Bogor, Depok, Tangerang, Bekasi Commuter Train crossing Bogor-Manggarai. This study uses the Analytic Hierarchy Process to analyze timeliness. With the number of informants taken as many as 12 informants consisting of five people from regulators, five people from operators, one expert in the field of railways and users of commuter train of Jakarta Bogor, Depok, Tangerang, Bekasi. From the measurement results, it was found that the Jakarta, Bogor, Depok, Tangerang, Bekasi Commuter Train was still experiencing delays, due to follow-ups and cross-changes in the operation pattern of the Jakarta Bogor, Depok, Tangerang, Bekasi Commuter Train which was still mixed with long-distance and freight trains, the construction of the Manggarai station as part of the Double Double Track project, the signaling system at the station. Manggarai also underwent changes and there were speed restrictions at Manggarai Station. Recommendations are to complete the construction of the Manggarai and Jatinegara stations which are useful for separating inter-city and urban rail travel, updating the signaling system on the crossing between Bogor Station-Manggarai Station and City Station which is now 30 years old, handling and improving level crossings with coordinate with related units.

On-Site Calibration Method for Line-Structured Light Sensor-Based Railway Wheel Size Measurement System.

Line-structured light has been widely used in the field of railway measurement, owing to its high capability of anti-interference, fast scanning speed and high accuracy. Traditional calibration methods of line-structured light sensors have the disadvantages of long calibration time and complicated calibration process, which is not suitable for railway field application. In this paper, a fast calibration method based on a self-developed calibration device was proposed. Compared with traditional methods, the calibration process is simplified and the calibration time is greatly shortened. This method does not need to extract light strips; thus, the influence of ambient light on the measurement is reduced. In addition, the calibration error resulting from the misalignment was corrected by epipolar constraint, and the calibration accuracy was improved. Calibration experiments in laboratory and field tests were conducted to verify the effectiveness of this method, and the results showed that the proposed method can achieve a better calibration accuracy compared to a traditional calibration method based on Zhang’s method.

Development and validation of a wear prediction model for railway applications including track flexibility

The simultaneous prediction of wheel surface wear is one of the most challenging tasks in the railway field, which requires the knowledge of vehicle–track dynamics, rolling contact mechanics, and other tribological phenomena. In this paper, a new model for predicting wheel profile wear is presented to study in detail the characteristics of wear in the railway. The model is able to consider the effect of track flexibility on wheel wear evolution. The proposed modelling approach includes a vehicle–track coupled model for vehicle dynamical simulation, the local contact model for wheel–rail interaction, and an energetic approach for surface wear evaluation. The whole model has been validated by the comparison with experimental data coming from Chinese high-speed railway lines. The results show that the new model assures high computational efficiency as well as reaches a good prediction accuracy. The proposed model allows the investigation of the role played by different track parameters related to track flexibility on the wheel and rail wear evolution. The influence of the fastener and railpad stiffness on the wheel wear evolution is presented, using the proposed model.

Optimization approach to the choice of explicable methods for detecting anomalies in homogeneous text collections

The problem of detecting anomalous documents in text collections is considered. The existing methods for detecting anomalies are not universal and do not show a stable result on different data sets. The accuracy of the results depends on the choice of parameters at each step of the problem solving algorithm process, and for different collections different sets of parameters are optimal. Not all of the existing algorithms for detecting anomalies work effectively with text data, which vector representation is characterized by high dimensionality with strong sparsity.The problem of finding anomalies is considered in the following statement: it is necessary to checking a new document uploaded to an applied intelligent information system for congruence with a homogeneous collection of documents stored in it. In such systems that process legal documents the following limitations are imposed on the anomaly detection methods: high accuracy, computational efficiency, reproducibility of results and explicability of the solution. Methods satisfying these conditions are investigated.The paper examines the possibility of evaluating text documents on the scale of anomaly by deliberately introducing a foreign document into the collection. A strategy for detecting novelty of the document in relation to the collection is proposed, which assumes a reasonable selection of methods and parameters. It is shown how the accuracy of the solution is affected by the choice of vectorization options, tokenization principles, dimensionality reduction methods and parameters of novelty detection algorithms.The experiment was conducted on two homogeneous collections of documents containing technical norms: standards in the field of information technology and railways. The following approaches were used: calculation of the anomaly index as the Hellinger distance between the distributions of the remoteness of documents to the center of the collection and to the foreign document; optimization of the novelty detection algorithms depending on the methods of vectorization and dimensionality reduction. The vector space was constructed using the TF-IDF transformation and ARTM topic modeling. The following algorithms have been tested: Isolation Forest, Local Outlier Factor and One-Class SVM (based on Support Vector Machine).The experiment confirmed the effectiveness of the proposed optimization strategy for determining the appropriate method for detecting anomalies for a given text collection. When searching for an anomaly in the context of topic clustering of legal documents, the Isolating Forest method is proved to be effective. When vectorizing documents using TF-IDF, it is advisable to choose the optimal dictionary parameters and use the One-Class SVM method with the corresponding feature space transformation function.

The problem of loss of solutions in the task of searching similar documents: Applying terminology in the construction of a corpus vector model

This article considers the problem of finding text documents similar in meaning in the corpus. We investigate a problem arising when developing applied intelligent information systems that is non-detection of a part of solutions by the TF-IDF algorithm: one can lose some document pairs that are similar according to human assessment, but receive a low similarity assessment from the program. A modification of the algorithm, with the replacement of the complete vocabulary with a vocabulary of specific terms is proposed. The addition of thesauri when building a corpus vector model based on a ranking function has not been previously investigated; the use of thesauri has so far been studied only to improve topic models. The purpose of this work is to improve the quality of the solution by minimizing the loss of its significant part and not adding “false similar” pairs of documents. The improvement is provided by the use of a vocabulary of specific terms extracted from the text of the analyzed documents when calculating the TF-IDF values for corpus vector representation. The experiment was carried out on two corpora of structured normative and technical documents united by a subject: state standards related to information technology and to the field of railways. The glossary of specific terms was compiled by automatic analysis of the text of the documents under consideration, and rule-based NER methods were used. It was demonstrated that the calculation of TF-IDF based on the terminology vocabulary gives more relevant results for the problem under study, which confirmed the hypothesis put forward. The proposed method is less dependent on the shortcomings of the text layer (such as recognition errors) than the calculation of the documents’ proximity using the complete vocabulary of the corpus. We determined the factors that can affect the quality of the decision: the way of compiling a terminology vocabulary, the choice of the range of n-grams for the vocabulary, the correctness of the wording of specific terms and the validity of their inclusion in the glossary of the document. The findings can be used to solve applied problems related to the search for documents that are close in meaning, such as semantic search, taking into account the subject area, corporate search in multi-user mode, detection of hidden plagiarism, identification of contradictions in a collection of documents, determination of novelty in documents when building a knowledge base.

An enhanced SHERPA (E-SHERPA) method for human reliability analysis in railway engineering

According to the European standard EN 50126 human reliability is a fundamental requirement in railway engineering. Notwithstanding that there are only few methods specifically developed for railway field. Trying to fill this gap, this paper proposes a human reliability analysis technique customized on railway applications to simulate a time-dependent model of the human error probability during the work shift. The first novelty of the proposed method is the use of customized task types for railway applications within a third-generation method. Furthermore, the concept of Eustress is considered to evaluate the impact of the stress on the operator performances by means of the Yerkes-Dodson law. The main novelty of the proposed method is the introduction of a simulator which provides the possibility of considering one or more breaks in the work shift allowing to simulate the error probability based on the duration of the break. The maintenance operations carried out on an Italian Automatic Train Protection System have been taken as case study to validate the proposed method in different scenarios. The results illustrate how a break during the working shift of the operator influences the probability of committing an error.

Consideration of methods for extracting and sharing ideas and tips focusing on "what is going well" in the railway field

Consideration of methods for extracting and sharing ideas and tips focusing on "what is going well" in the railway field

Bi-TLLDA and CSSVM based fault diagnosis of vehicle on-board equipment for high speed railway

Vehicle on-board equipment (VOBE) is a significant component of the control system of high-speed railway train, the fault diagnosis of VOBE mainly depends on maintenance experience, which is inefficiency. The fault data of on-board equipment is described by natural language. Due to its unstructured, high-dimensional and unbalanced fault class distribution, it has become a challenge in fault diagnosis. In this paper, bilevel topic labeled latent Dirichlet allocation for extraction feature of fault text data is proposed. Firstly, label information is set according to prior knowledge of railway field. Then, local topics and global topics are defined for two level fault types of VOBE. The fault feature space generated by Gibbs sampling from local topics and global topics contains two level fault features, which are conducive to fault text classification. Finally, considering the imbalanced distribution of fault class, cost sensitive support vector machine based fault text classification is proposed. By using actual fault data of on-board equipment of China Railway Corporation, the accuracy, precision and F1-score are used as performance indicators to compare the proposed method with other fault diagnosis methods. The results show that the accuracy of the proposed method is 90.3%, which is about 2% higher than that of the suboptimal method, and the average recall, precision and F1-score of various fault classes are 77.9%, 91.8% and 83.4%, respectively, which outperforms other fault diagnosis methods.

A study on squeal noise reduction considering the pad shape of the disc brake system for urban railway vehicles

In this paper, to help reduce the squeal noise produced during the braking of urban railway vehicles, the shape of the disc brake pad was investigated to relieve contact stress. To analyze the disc brake system to identify the source of the squeal noise, a finite element model of the disc brake system was used, including the peripheral brake parts to increase accuracy. A complex eigenvalue analysis was performed to predict squeal noise generation. Verification was carried out using domestic urban railway field test results to confirm the accuracy of the analysis model. A pad shape that relieves contact stress is proposed to reduce squeal noise produced by nonuniform contact between the disc and pad. The results of this study can be utilized for future studies on squeal noise reduction.

Seismic running safety of trains and a new type of seismic-isolation railway structure

Abstract Until now, seismic-isolation structures have not yet been applied in the railway field. The reason is that though a seismic-isolation structure can reduce the inertial force to the structure, the energy absorption causes big response displacement on the structure, which adversely effects the running safety of the trains supported by the structure. In this paper, a methodology for seismic running safety assessment is introduced, and a new type of seismic-isolation foundation is proposed, which can convert the seismic response displacement in the lateral direction of track to the longitudinal direction that has a less adverse effect on the running safety of the train. The isolation foundation is composed of FPS (Friction Pendulum System) slider, concave plate and guide ditch. Moreover, through model experiments and 3D numerical simulation, it is verified that the proposed foundation can keep both the effects of the seismic isolation and the running safety of the train during an earthquake.