Hasil untuk "Railroad engineering and operation"

Raphael Lúcio Reis dos Santos, Conrado de Souza Rodrigues, Guilherme de Castro Leiva et al.

PurposeThis paper provides a comprehensive analysis of the Brazilian freight railway system, examining the efficacy of the current concession renewal model in light of persistent structural problems such as market concentration, cargo dependence on export commodities and underutilization of the network. Situating Brazil within the broader international debate on railway reforms, the paper evaluates whether the ongoing early renewal of concessions can deliver a more diversified and competitive freight system.Design/methodology/approachThe study adopts a sequential mixed-methods research design that integrates longitudinal quantitative analysis with qualitative institutional and policy evaluation. The quantitative component examines time-series indicators published by ANTT, DNIT and INFRA S.A. from 1999 to 2023 to identify structural patterns in traffic growth, investment, safety and market concentration. The qualitative component employs a process-tracing logic to reconstruct the evolution of concession renewals and the implementation of Railway Law 14.273/2021, drawing on concepts from regulatory economics, institutional theory and industrial organization. These empirical streams are synthesized through an analytical framework that connects three dimensions - regulatory design, market structure and system performance - allowing for a systematic assessment of how Brazil's institutional configuration shapes incentives, competitive dynamics and network utilization.FindingsThe analysis confirms that the early renewal of concessions has successfully secured substantial private investment for capacity expansion on existing trunk lines. However, it has perpetuated the vertically integrated model, reinforcing the market power of incumbent operators and failing to significantly promote intramodal competition or cargo diversification. The system remains dominated by iron ore and agricultural commodities, with general cargo representing a minuscule share. The new authorization regime and short-line railway policies present a viable pathway for market opening but face significant operational and institutional barriers to implementation.Originality/valueThis research offers a timely and critical assessment of a pivotal moment in Brazilian railway policy. It moves beyond a simplistic evaluation of volume growth to a structural analysis of market failures and the interplay between concession renewal and regulatory innovation. The findings provide actionable insights for policymakers in Brazil and other emerging economies seeking to balance private investment with public interest goals in railway infrastructure, highlighting the necessity of complementary, pro-competitive measures alongside financial investment.

A. N. Savos'kin, N. S. Lavlinskaya, P. Yu. Ivanov

Introduction. In the undercarriage of modern locomotives hydraulic vibration dampers are widely used to dampen vertical vibrations that occur in the axlebox stage of the spring suspension. Their resistance force is directly proportional to the deformation rate of the spring set. High levels of vibration frequencies and amplitudes in the axlebox stage lead to a significant increase in the strain rate and dissipative forces, which causes frequent failures of hydraulic vibration dampers. Therefore, issues related to improving the performance of axlebox hydraulic dampers are actual.Materials and methods. In order to evaluate the effectiveness of elastically protected hydraulic vibration damper in axlebox suspension, the authors studied the vibrations of a simplified model of a 2ES5K electric locomotive with a typical layout of the axlebox stage of spring suspension and a circuit with an elastically protected hydraulic vibration damper. The authors used a high-frequency random process as a kinematic perturbation of vibrations. The system of differential equations was solved in the MatLab — Simulink software package by numerical integration using the Runge — Kutta method of the fourth order. As a result of the solution, realisation of stationary and ergodic random processes were obtained. Results. The comparison of the obtained characteristics of random processes of vibrations of these two options showed that the use of an elastically protected axlebox vibration damper significantly reduces the frequency range and amplitudes of dissipative forces, which ensures a reduction in the number of axlebox damper failures and an increase in the number of runs before replacement is required.Discussion and conclusion. The shown efficiency of using an elastically protected axlebox vibration damper allows increasing the reliability of the damper. In order to determine the distance run between overhauls, it is necessary to carry out a controlled operation cycle or test the prototype axlebox assembly with the elastically protected vibration damper and measure the parameters of such assembly.

JIANG Chaoyong, ZHAO Xinyuan, WEI Wei et al.

The fatigue failure of metro frame may occur at the weld toe and weld root of the welded joint. Therefore, an effective fatigue evaluation method is needed to analyze the fatigue reliability of the bogie comprehensively. To solve this problem, based on the effective notch stress method, the overall finite element model of one metro frame and the local mesh refinement finite element model of the welded joint between the wing plate of the motor suspension seat and the cross beam were established, and the effective notch stress distribution at the weld toe and weld root of the welded joint was obtained. According to Miner damage theory and the corresponding S-N curve, the cumulative damage of effective notch stress method and nominal stress method were calculated. The results show that fatigue failure is more likely to occur at the root of the joint. In addition, the effective notch stress method is safer than the nominal stress method. For further study the influence of different loads on damage, by comparing the cumulative damage results of each load, it was found that for the effective notch stress, the five loads with large damage are torsional load, motor transverse load, motor vertical vibration load, motor driving load and gearbox vertical vibration load, of which the torsional load accounts for the largest proportion, up to 30%-60%. The safety and applicability of the effective notch stress method in the fatigue evaluation of subway vehicle frame was verified.

Wenye LIU, Lixuan KANG, Haitao LIU et al.

The application conditions of rail transit converter are relatively strict, which requires high reliability and service life of converter and IGBT devices. In order to improve the junction temperature of IGBT and the application life and reliability of the converter, a general loss calculation model was constructed based on the working mode of locomotive converter module to realize the on-line estimation of the junction temperature of IGBT devices of the converter; On this basis, combined with the application scenario of rail transit, a comprehensive active junction temperature control method was designed from the two dimensions of switching loss and heat dissipation system. Simulation and experiments showed that the implementation of active junction temperature control was feasible.

Yanhong SHI, Qian CHEN

At present, there are mainly two communication modes in network control system of high-speed EMU in China: bus-type and switched-type. In some special cases, the two communication modes trains with the same speed grade need to realize connectivity. However, there are some differences between these two kinds of network control system, such as technical characteristics and working principle, the connectivity of this two systems is difficult. Therefore, a reconnection scheme of bus and switched high-speed train network control system was proposed, including train network topology scheme, adaptive reconnection strategy, initial operation process realization and connectivity control, etc., and verified on Fuxing EMU. The verification results show that the scheme can realize the connectivity control of different communication types of trains, which has a very important practical significance to improve the efficiency of train operation.

Haitao ZHANG, Nan JIANG

Wide bandgap power devices with excellent performance over traditional silicon power devices have been introduced as the prime candidate for power electronics applications. However, interconnections on the chip topside in the traditional packaging are now limiting the lifetime of wide bandgap power devices. It is necessary to replace aluminum bond wires with copper bond wires, ribbons, and lead-frames with the help of bond buffer technologies to ful fill the requirements of wide bandgap power devices under high temperature operation conditions. The reliability performances of different bond buffer technologies and bonding materials under power cylcing tests were reviewed. The Cu-Invar-Cu bond buffer combined with Cu bonding material showed the most robust power cycling capability among all bonding materials. Failure analysus shows that the weak point of the packaging of wide bandgap power devices has been changed from the bonding material to the Al₂O₃ ceramic substrate or the aluminum metallization layer of the chip.

A. Ya. Kogan

The problem of wave-shaped rail wear is highly relevant for rail transport. The paper presents a mathematical model of the formation and development of wave-shaped rail wear. The task of estimating vertical wear of the rail head under the axles of electric locomotives passing in the traction mode is considered. A technique has been developed that allows building chain of calculations that determine the formation and development of a wave-shaped rail head wear. A specific calculation example is given, illustrating the process of propagation of a wave-shaped wear from the source of its formation in the direction of train motion. An example of the calculation allows drawing the following conclusions:1. Wave-shaped wear primarily occurs when the shock interaction of the wheel of an electric locomotive moving in the traction mode and a rail thread having imperfections of the rolling surface. Such imperfections, among others, may be a joint with a significant gap or a “step down” in the direction of the locomotive, as well as a welded joint with defect 46.3-4.2. Wavelength of the wave-shaped rail wear, its configuration and amplitude of the fundamental tone are determined mainly by joint oscillations of the wheel-motor unit of the locomotive and the track infrastructure in the field of high-frequency oscillations (120 – 180 Hz).3. Multivariate calculations showed that in steady state, the distribution speed of wave-shaped rail wear in the direction of train motion (as a function of the number of axles of electric locomotives passed in traction mode) is directly proportional to the vertical load at the wheel and rail contact in the slip zone 0≤Q≤F/(2nψk), is inversely proportional to wear resistance C and significantly depends on the parameters of the undercarriage of the electric train and the track superstructure.

Michal Bubeník

Článek se zaměřuje na využití formálních metod při vývoji softwaru pro bezpečnostně kritické systémy v dopravě. Takové systémy mají narůstající složitost a musejí vyhovovat určitým požadavkům na kvalitu. Formální metody jsou zařazeny do procesu vývoje softwaru. Použití vybrané formální metody Event-B je demonstrováno na specifikaci chování železničního přejezdového zabezpečovacího zařízení.

S.Sunitha Nanthini, S. Anusubha, G. Jenisha

cases where there has been a fuel leak due to disruption of fuel lines or rupture of the fuel tank. Out Fully electric vehicles are being introduced to the of hundreds of crash tests ANCAP has experienced passenger car market in addition to the already popular one minor fire, where an electrical short ignited some hybrid vehicles. There are existing and proposed foam plastic insulation near the crushed radiator. standards for the design of these vehicles to reduce the Another post-crash hazard from conventional vehicles risk of occupants and rescue personnel being exposed is leakage of battery acid. to hazards such as corrosive chemicals, toxic fumes, Fully electric and electric hybrid vehicles potentially fire and electric shock in the event of a crash. Some introduce new types of post-crash hazards. This paper manufacturers are understood to be working with reviews those potential hazards and provides advice rescue organisations to develop appropriate procedures for minimising risks. It is stressed, however, that for dealing with these crashes. experience with electric vehicles is limited and that New Car Assessment Programs (NCAPs) have this advice will need to be reviewed as more subjected several petrol-electric hybrid vehicles to the information becomes available. It is also 64km/h frontal offset crash test, 50km/h barrier side acknowledged that vehicles manufacturers have put impact test and the 29km/h side pole test. No problems considerable resources into developing safe and with the electrical systems or batteries were reliable electrical systems for the current generation of encountered. These tests have generally involved electric vehicles. A serious incident involving a vehicles with lead-acid or NiMH batteries. Lithium-ion lithium-ion car battery is considered to be highly batteries are becoming popular and these might unlikely but it is important that crash test organisations introduce different hazards for crash-test and rescue and rescue organisations understand and are prepared personnel. for the potential hazards. In October 2010 a research crash test of an electric car ELECTRIC VEHICLE TECHNOLOGY with a Lithium-ion battery was conducted by Electrically-propelled automobiles have been in use for Australasian NCAP and Japan NCAP. Additionally, more than a century: Euro NCAP has also assessed a number of vehicles “Stored electricity finds its greatest usefulness in powered by Li-ion batteries. This paper reviews the safety hazards and outcomes associated with those propelling cars and road vehicles, and it has been for tests and provides draft advice for crash test and rescue this application, primarily, that the Edison storage organisations. battery has been developed. Mr Edison saw that there INTRODUCTION are two viewpoints: that of the electrical man with his instruments, his rules of efficient operation and The Australasian New Car Assessment Program reasonable life of the battery, his absolute knowledge (ANCAP), US Insurance Institute for Highway Safety that the same care should be given a vehicle battery (IIHS) and Euro NCAP have conducted 64km/h frontal that is given a valued horse or even a railroad offset crash tests since the mid 1990s. Japan NCAP locomotive; and that of the automobile driver, who and Korean NCAP also conduct this test. These simply wishes to go somewhere with his car, and who, organisations have also conducted 29km/h side pole when he arrives somewhere, wishes to go back. And in tests on many vehicle models. the long-promised storage battery the highly practical Almost all the tested vehicles have had conventional nature of Edison’s work is once more exemplified in that he has held uncompromisingly to the fuel systems (petrol or diesel). There have been several

Donatas Rekus, Vilma Kriauciūnaite-Neklejonoviene

Roads, railroads and streets are one of the most important infrastructure, so it is very important rightly construct and to make control geodesic pictures of them. In order to qualitatively and effectively carry out the following operations, it is necessary to assess the methods (advantages and disadvantages) used for these works. The work describes the usage of the measureaments devices, their specifications, data analysis and comparision with the most eficient device. Railway tracks require more thorough maintenance and analysis than regular roads for cars. Defects are here noticed and recorded by using special equipment. Construction of railway roads and their exploitation requires optimal accuracy and monitoring of surveying. It is related to maximum allowed speed of trains, the environment, transport and human safety. Their monitoring needs to be improved by applying geodetic devices for surveying. Comparing analogous surveying conducted using EM140 machine with that of geodetic equipment, one can see the advantage of geodetic surveying. Technical gaps in the surveying process, data storage and procession were evaluated as well. It was discovered that maintenance and monitoring works should be pursued more frequently using high accuracy geodetic equipment. The main aim of this article is to evaluate differences of the technological process and control technology by conducting geodetic investigation in railway objects. DOI: http://dx.doi.org/10.5755/j01.sace.23.2.21134

E. N. Efimova, P. B. Manevich, A. V. Shmelev

One of the key problems of organizing an effective The article considers problems of the influence of technical transportation process is an adequate reflection of the current and technological parameters of freight transportation by rail on pricing factors in the tariff system. This can be done on the basis of the cost price for tariff purposes, the distribution of the cost of the the development of appropriate models for determining the cost initial-final operation between loaded and empty cars, determinaof transportation. Modeling the cost of transporting freights by rail tion of coefficients taking into account the length of cars and the for tariff purposes is based on determining and assessing the rela-distance of transportation, as well as the methodology for the distionship between transportation costs and work indexes. tribution of costs between the initial-final and motion operations. Proposed updated methodology for constructing parametric models for determining the cost of transportation of freights for tariff setting purposes includes: method of itemized distribution of expenditures between non-commercial organizations and affiliated subsidiaries in terms of infrastructure and traction; procedure for allocating the costs, attributed to affiliated subsidiaries, to the indexes “ton-kilometer gross” and “car-kilometer”; system of itemized distribution of freight costs for the indexes of the transportation operation, as well as the system for calculating the aggregate expenditure rates (AER) used in parametric models of the cost price; actualized assessment of the influence of the length of the car on the cost value for tariff setting purposes; procedure for allocating the cost of initial-final operations between loaded and empty cars. The developed parametric models for calculating the cost of transportation for tariff purposes for transportation by the locomotive of the JSC “Russian Railways” take into account such factors as the distance of transportation, the weight of the container and the length of the car, its loading, the type of shipment. Within the framework of creating new parametric models, the following factors have been updated: coefficients that take into account the length of the car; coefficients that take into account the effect on the cost of production up to the distance of transportation in connection with the change in the relative distance of carriage of the car as part of mixed and transfer-and-export trains; coefficients depending on the type of shipment.

SHEN Huabo

In view of the shortages of low automation and poor generality in the process of EMUs debugging, a kind of intelligent acquisition device based on wireless transmission was designed based on wireless transmission. The device consists of command acquisition controller and handset. The acquisition controller connected the EMUs with electric coupler, using the embedded wireless module to communicate with the handheld machine to realize the real-time acquisition and control of 196 kinds of command signal data. The device had completed the actual performance tests such as power test, insulation resistance test and voltage polarity test. The test results showed that the device has good stability and safety.

G. S. P. Reddy, Rama Rao, V. Harish et al.

The everyday workplace of railroads is backbreaking and frequently includes high-hazard activities. These operations has its impact on railways crew and public people who lives along the town and cities. To avoid the employees and public's exposure to risk, railway companies uses safety training programs[1] , advanced technology concepts like data analytics and machine learning to analyze about frequent accident occurring zones and safety precautions to be taken in advance. So in this paper we are proposing an visualization model for identifying the frequent occurrence of railway accident zones so as to take enough precautions to avoid them. Here we will be collecting the data on the frequently occurring railway accidents and the causes for it. After the data is been collected, we will be analyzing the data and presenting the information about most frequent and less frequent accident prone areas using visualization tools which provides the clear picture of incidents so as certain precautions or counter measures will be taken at proper times to minimize railway accidents. The results of the analysis done can be used to make and communicate decisions about accidents so as to minimize them.

Yu. S. Romen, O. A. Suslov, A. A. Balyaeva

When implementing new or modernized rolling the train in most cases is in the range of 0.9-0.95 and varies de-stock, one of the main problems is the provision of both traffic pending on the position in the track of a group of wheelsets. The safety, and the strength of the carriage and the ways that are de-correlation level of the frame force measured in the carriage and termined by forces in the wheel - rail system. It is almost impossible the sum of lateral forces by its average values is 0.98. A practical to directly measure the forces of interaction between the crew and method for determining the forces of interaction with respect to the track. Their determination can be carried out by measuring the stresses in the neck of a rail was proposed by Schlumpf. It involves stresses in rails, the interdependencies of which with forces are of determining the difference of the moments in the two cross sections a probabilistic nature. Correlation of the strength and stresses for of the rail neck with the angular moment of resistance to bending being equal. In this case, when the scale factors are equal to the difference of the moments, the lateral force is determined. The calculations were made by subtracting electrical signals (four strain gauges were included in the shoulders of the Wheatstone bridge), and a separate bridge was used to determine the vertical load. Errors in determining the lateral force are due to inaccurate location of the sensor sticking, the difference in the dimensions of the rail neck and the displacement of the point of application of the vertical load on the rail head. However, since the maximum forces are realized when the wheel climbs on the rail, this displacement varies insignificantly. Therefore, the results obtained can be used in conducting certification tests. The method of digital processing of data on stresses at three points of the rail neck requires for its implementation more strain gages, but the accuracy of its results is much higher, since it depends only on the errors of preliminary calibration of the cross sections. The error in calculating the forces does not exceed 4%, which shows the expediency of using the three-point method in determining the interaction forces to establish the conditions of circulation.

Mária Chovancová, Vladimír Klapita

Príspevok sa zaoberá implementáciou vybranej techniky Teórie obmedzenia za účelom identifikovania hlavných príčin nežiaducich dôsledkov v oblasti zásobovacej logistiky. Potreba stanovenia nežiaducich dôsledkov zásobovacej logistiky súvisí predovšetkým s nepriaznivým vplyvom na nákladovosť, ziskovosť a kvalitu celého dodávateľského reťazca. Problematika implementácie sa predovšetkým zaoberá jednotlivými krokmi postupu súvisiaceho s tvorbou konkrétneho stromu (techniky) Teórie obmedzenia. Zmyslom danej techniky je identifikácia hlavných príčin, ktoré majú najvýznamnejší vplyv na negatívne dôsledky zásobovania na dodávateľský reťazec.

A. T. Os'minin, E. A. Sotnikov, M. A. Os'minin

Conditions for the effective organization of repair-track works using technology of lengthy closing track sections for a day and more, as well as the "windows" of long duration. Technology of long-term closure of sections is becoming more common. In 2016, more than 60 % of the total amount of repair and reconstruction of infrastructure is performed using such a method of organization of work. This minimizes the total execution time for repair and track work and accordingly optimized their impact on the operational activities of sections and directions. The concept of transit directions is established, repair track works on them must be performed only by in-transit technology. A list of such areas, including interconnected transit areas was made, in which work planning is carried out comprehensively. When solving the problem of building schedules of long closures and "windows" of long duration such new concepts as "transit period of one-off closure of section", "shift of section closure in transit", "common planning period of section closures in transit" were determined with number of others, using of which is gradually determined by the duration of works by the technology in transit, including interconnected transit directions. Conditions are established for allocating limiting transit directions which are advantageous for performing works by "in transit" technology. The principles of constructing variant train schedule on single-track lines was developed with the definition of sections and segments for which the execution of repair works is performed by in transit technology. Application of the proposed methodic provisions will streamline the system of using advanced methods of performing repair and track works.

Miroslav Blatnický, Ján Dižo

Článok sa zaoberá renováciou poškodeného netypizovaného navijaka pracovného stroja, ktorého poškodenie nastalo vplyvom preťaženia v prevádzke z dôvodu nešpecifikovaného zaťaženia, čo môže predstavovať určitý stupeň nebezpečenstva. Z tohto dôvodu bude vykonaná tvorba výkresovej dokumentácie z reálneho zariadenia, aby bolo možné okamžite zisťovať vstupy slúžiace pre analytický dimenzionálny výpočet za účelom stanovenia hodnoty maximálnej prípustnej hmotnosti zaveseného bremena na danom navíjacom zariadení.

Samuel J. Levy

L. Posthuma, A. Bjørn, M. Zijp et al.

SHAO Zhi-he, HE-zai, LIU Xue-quan

System maintainability allocation method was expounded. Function diagram and mathematical model on maintainability for EMUs electric traction systems were established, and weighted method was used for the distribution. EMUs electric traction systems target allocation was analyzed, and the weak links in its maintainability design was identified, which provided reference and guidance for the design of EMUs electric traction systems repair element (fault detection and isolation, accessibility, convertibility, adjustment).