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We describe the process of forming the gash in the tank of the first wagon of the freight car n. 50,325 during the accident that caused the known Viareggio disaster in 2009. Analyzing the findings of the accident and details of the fracture surfaces on the tank, as well as the deforming state, both of the tank around the hole and the element of the infrastructure that caused the hole, the cause-effect relationship between the traces left by the impact on the two structures involved is identified throughout the hole extension. In addition, we verify the geometric, morphological, physical and mechanical compatibility between some traces of the impact of the same tank with other elements of the infrastructure, to remark the extraneity of these with the formation of the gash in the tank. • The role of the wing rail in the Viareggio disaster • Image analysis can completely replace the instrumental analysis on the finds • The breaking mode of the railway tank allows to trace the dynamics of the impact [ABSTRACT FROM AUTHOR]

During the operation of freight cars, uneven wear occurs in the central bowl of the rail truck bolster. This article aims to determine the concentration of the filler of the composite material to reduce the wear of the central bowl of the rail truck bolster. In this work, for the first time, a mathematical model of the distribution of the filler concentration in the projected composite tape was obtained. To reduce the wear of the working surface of the central bowl of the rail truck bolster, as well as to ensure uniform wear distribution, it is proposed to weld a composite tape with variable tribomechanical properties using contact welding. The wear value of the working surface of the central bowl of the bolster of the rail truck bolster when using composite tapes of compositions Fe-Cr-Ni-Cr 3 C 2 and Fe-Cr-Ni-TiC with contact welding was 0.15–0.18 mm per 10,000 km - for a loaded freight car and 0.08–0.10 mm per 10,000 km for an empty freight car. According to the amount of wear, the value of the service life of the center plate assembly is predicted, which is 320,000–420,000 km. [ABSTRACT FROM AUTHOR]

The poem "Tract House" by Lisa Russ Spaar is presented. First Line: In swathes of remnant farm; Last Line: undone. Then run.

Purpose. The scientific work is aimed to: 1) analyze the technical condition of freight cars and technological methods used in the repair; 2) identify possible ways to improve resource of freight car bogies; 3) develop a mathematical model to describe the wear geometry of the original surface of bogie center pad at the corresponding life cycle of a freight car. Methodology. In order to solve the problem complex of increasing TBO of freight car bogies the methods for the synthesis, analysis and systematic approach were used. In addition, the use of mathematical modeling unit, solid state physics, the theory of friction and wear of solids. Findings. The analysis of the technical condition of freight cars has shown that up to 15% of the faults falls on the bogies. A separate element of the repaired bogie is a bolster. At this the center pad is recovered most often. The center pad wear is uneven and the technological methods used for the repair, do not allow providing uniform wear due to which there is a need in premature repairs. One of the ways to improve the center pad resource during repair is the application of welding or sputtering deposition, but with providing discrete strength and durability in the longitudinal and transverse directions of the car axis, respectively. In order to establish the boundaries of the distribution of renewable material along the center pad diameter it was considered the fatigue wear process in cooperation with center plate and described the geometry of the surface of the center pad wear. Originality. Technical condition of freight car bogies according to wear criterion was analyzed in the paper. It is shown that the dynamics of bogie faults has a positive character. In addition, a significant place among the repaired parts takes the bolster, and a special loaded place is the center pad. To describe the geometry of wear for the first time a mathematical model for determining the initial surface of the center pad in the relevant life cycle of freight car bogie was proposed. Practical value. The results allow us to establish the geometry of the wear surface bolster center pad when interacting with center plate of freight car from a position of occurrence of fatigue wear, that is, on the strength criterion.

In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented. The analysed brake disc is used in rail freight wagons and possesses a load capacity of 22.5 tons per axle. Two of the divided rail freight brake discs are mounted on each axle. With the aid of numerical analysis, the thermal dissipation properties of the brake disc were optimised and ventilation losses were reduced, and the numerical results were compared with experimental results. A one-way fluid-structure interaction analysis was performed. A computational fluid dynamic model of a divided rail freight brake disc, used to predict air flow properties and heat convection, was incorporated into a finite element model of the disc and used to evaluate the temperature of the disc. A numerical parametrical optimisation of cooling ribs of the brake disc was also performed, and novel optimised cooling ribs were developed. A transient thermal numerical analysis of the brake disc was validated using temperature measurements obtained during a braking test on a test bench. The ventilation losses of the brake disc were measured on a test bench specifically designed for the task, and the losses were compared to the simulation results. The experimentally obtained ventilation losses and temperature measurements compared favourably with the simulation results, confirming that this type of simulation process may be confidently applied in the future. Through systematic optimisation of the divided rail freight brake disc, ventilation losses were reduced by 37% and the mass was reduced by 21%, resulting in better thermal performance that will bring with it substantial energy savings. [ABSTRACT FROM AUTHOR]

Abstract The study deals with distribution of freight cars of various forms of ownership within the railway network. Some variants of rail network topology were analysed by applying the graph theory and considering complexity of distribution of cars belonging to forwarding companies by routes. The railway subsystem itself should be considered as a compromise between its stability and flexibility. Thus, optimization model which formalizes technological process of freight car fleet management of operator companies has been developed. The objective of the given model is presented in the form of total operating cost and relevant set of constraints that takes into account technological conditions of route formation. On the basis of the systematic approach it has been proved that the increase of railway transport competitiveness is possible provided the railway subsystem acquired invariance properties. The mode optimization model adequately reflects the terms of transportation process, ensures the reduction of transportation costs under the condition of satisfaction of clients' requirements and provides for the formation of computer-aided fleet management technology for cars of different forms of ownership. Taking into account the theory of computational complexity, it is reasonable to choose heuristic method based on mathematical apparatus of genetic algorithms to obtain the optimal car distribution plan according to the routes. [ABSTRACT FROM AUTHOR]

The yoke is a safety-critical component of the coupler assembly of railway freight cars and is responsible for absorption of impact loads during service. The present study investigates the root cause of low impact toughness of a particular batch of yoke castings produced in Texmaco Steel Foundry. Examination of microstructure and fracture surface of specimens extracted from the castings reveals the presence of a substantial number of macro- and microporosities. The fracture morphology confirms that the presence of such large number of porosities increases stress concentration and lowers the load-bearing area, resulting in brittle failure and low impact toughness. EDX analysis indicates that these porosities were caused by entrapment of gases during solidification. Subsequent examination indicates that the porosities were caused due to gases generated by combustion of resins/binders used in the sand system or improper venting during the pouring operation. [ABSTRACT FROM AUTHOR]

Paper contains a report of the part of works conducted in the research and development project concerned with a modernization of freight wagons during their periodic repair. The aim of this research was to obtain better exploitation conditions of freight cars. Two elements of those works are presented: a computer aided analysis of the freight car's CAD model and results and analysis of the real object elements' vibrations during exploitation. The aim of numerical analysis was to determine the maximal permitted speed at which the car does not go off the rails. These tests were performed using the "Motion Simulation" module of the software of the CAD/CAE/CAM class Siemens PLM NX. The real freight car's elements vibration were measured and analysed in order to verify if it is possible to create a mechatronic approach for technical condition analysis of modernized freight cars during their exploitation based on their dynamic response as well as to validate the CAD model of the considered freight car. [ABSTRACT FROM AUTHOR]

In this study, simulations of shunting impacts for groups of freight cars that include up to six cars are considered. The simulation technique employs a white-box improved dynamic model of friction draft gear considering all its components and detailed finite element models of the freight cars. The key differences between the one-to-one shunting impact and the impact of long groups of cars in terms of features of the draft gear deflections and the coupler force time history are discussed. We present an example of dynamic finite element analysis for the car body using the coupler force time history obtained from the shunting impact simulation. [ABSTRACT FROM AUTHOR]

Purpose. Scientific paper is aimed at disclosing the existing problem of the «reliability» definition and provides a reasoned definition of the term. The study assumes the development of a complex that includes the methodology and appropriate terminology that will be true. Methodology. Currently there is reliability theory in the special case of the probabilistic and statistical theory, which is used to determine or predict the occurrence of object failures. Within the existing theories the term «reliability» is formulated, the parameters related to it are described. Findings. On the basis of the conducted analysis of the research within the existing theory of reliability and personal considerations of the authors, they formulated a definition of the term «reliability». The methodology and study of the object reliability on the example of a freight car was proposed. Originality. The authors proposed a new definition of the «reliability» term. Namely: reliability is an assessment of the ability of an object to maintain the original property within the established limits and temporary space, in the conditions of storage and transportation, as well as to perform the required functions in predetermined modes of operation with maintenance and repair facility. The reliability parameters include: reliability, durability, maintainability and safety that characterize the object. Also a methodology for developing and study the reliability of a freight car was developed, which comprises: 1) design, technological and operational reliability; 2) scientific experiment, including the modeling of the freight car in different conditions and operating modes; 3) the reliability theory is presented as combined or modified, covering the mathematical and physical foundations; 4) Bayesian statistics that describe the different states of a freight car with a breakdown of its basic components and with the appropriate probability for each component to describe the overall reliability. Practical value. The results of the study allow to provide a full and accurate picture with a corresponding failure of a freight car and to improve approaches to the construction and study of the reliability of the car overall.

The paper presents the results of experimental and computational studies of fatigue resistance of full-scale samples of the pivot assembly and side wall rack sealing assembly of a gondola car of 12-4106-01 model. It is found that their operating life is determined by fatigue resistance of welded joints of structural elements of the assembly. Their fatigue strength is equal from 12.1 MPa (side wall rack sealing assembly) up to 33.6 MPa (pivot assembly). Sections of fatigue cracks initiation, regularities of their propagation and fatigue strength of structures were established. As shown by calculation of the car body stressed state, the fatigue strength values ensure operation for 34.1 and 57.0 years, for the pivot assembly and side wall rack sealing assembly, respectively, before appearance of the fatigue crack. 9 Ref., 2 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental-calculation studies of fatigue resistance of full-scale samples of the bolster assembly and side wall rack sealing assembly of a gondola car of 12-4106-01 model. It is found that their operating life is determined by fatigue resistance of welded joints of structural elements of the assemblies. Their fatigue strength is equal from 12.1 MPa (side wall rack sealing assembly) up to 33.6 MPa (bolster assembly). Sections of fatigue cracks initiation, regularities of their propagation and fatigue limit of the structure were established. As shown by calculation of the car body stressed state, the fatigue limit values ensure operation for 34.1 and 57.0 years for the bolster assembly and side wall rack sealing assembly, respectively, before appearance of the fatigue crack. [ABSTRACT FROM AUTHOR]

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The main task of a draft gear coupler (shock absorber) installed on its movable part is to reduce the longitudinal forces in the formation of the train on the humps and at transient modes of the train. Its serviceable and effective action ensures the safety of the train itself as well as that of the goods transported. In the study of the longitudinal loading of a carriage the problem of improving and introducing new high-performance couples becomes urgent. We designed the constructions and mathematical models of advanced shock absorbers PMC-RBP-120, PMC-RBE-120, AVC-120P, AVC-120E, PA-120 and PA-120M. We managed to obtain a statistical distribution of the longitudinal forces affecting the movable part of the train through the automatic coupler of the carriage equipped with promising devices, under various loading conditions. The results of the calculations of the statistical distributions were used for the calculation and evaluation of performance effectiveness indicators of draft gear couplers as well as the assessment of the likelihood of parametric failure of the devices. [ABSTRACT FROM AUTHOR]

The article is devoted to the measuring methods used to determine the high limit of horizontal cross forces applied to the track generated at the curved movement of freight-car truck equipped with elastic side bearings. Based on the investigation of the measuring scheme of the freight-car truck wheels running upon the rail with its curved movement along the straightway part and the determination of magnitude of forces applied to the freight-cat truck at the moment considering a number of conditions, the authors develop a measuring formula used to determine of higher limit of horizontal force in the wheel and rail interaction. Further, on the foundation of comparison of calculations based upon the formula with the results of computational modeling of freight-car movement, the authors prove its consistency for preliminary quality evaluation of impact of tribological and elastic characteristics of a side bearer on the interaction between the projected freight car and the way. The authors also use it to determine the range of possible indexes for these parameters which are to be further specified with the results of the mathematical modeling of freight car movement. [ABSTRACT FROM AUTHOR]