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This study aims to propose a vertical coupling dynamic analysis method of vehicle–track–substructure based on forced vibration and use this method to analyze the influence on the dynamic response of track and vehicle caused by local fastener failure.

The track and substructure are decomposed into the rail subsystem and substructure subsystem, in which the rail subsystem is composed of two layers of nodes corresponding to the upper rail and the lower fastener. The rail is treated as a continuous beam with elastic discrete point supports, and spring-damping elements are used to simulate the constraints between rail and fastener. Forced displacement and forced velocity are used to deal with the effect of the substructure on the rail system, while the external load is used to deal with the reverse effect. The fastener failure is simulated with the methods that cancel the forced vibration transmission, namely take no account of the substructure–rail interaction at that position.

The dynamic characteristics of the infrastructure with local diseases can be accurately calculated by using the proposed method. Local fastener failure will slightly affect the vibration of substructure and carbody, but it will significantly intensify the vibration response between wheel and rail. The maximum vertical displacement and the maximum vertical vibration acceleration of rail is 2.94 times and 2.97 times the normal value, respectively, under the train speed of 350 km·h⁻¹. At the same time, the maximum wheel–rail force and wheel load reduction rate increase by 22.0 and 50.2%, respectively, from the normal value.

This method can better reveal the local vibration conditions of the rail and easily simulate the influence of various defects on the dynamic response of the coupling system.

In this study, a finite element model of a box-girder bridge along with the railway sub-track system is developed to predict the static behavior due to different combinations of the Indian railway system and free vibration responses resulting in different natural frequencies and their corresponding mode shapes.

The modeling and evaluation of the bridge and sub-track system were performed using non-closed form finite element method (FEM)-based ANSYS software.

From the analysis, the worst possible cases of deformation and stress due to different static load combinations were determined in the static analysis, while different natural frequencies were determined in the free vibrational analysis that can be used for further analysis because of the dynamic effect of the train vehicle.

The scope of the current investigation is confined to the structure's static and free vibration analysis. However, this study will help the designers obtain relevant information for further analysis of the dynamic behavior of the bridge model.

In static analysis, the maximum deformation of the bridge deck was found to be 10.70E-03m due to load combination 5, whereas the maximum natural frequency for free vibration analysis is found to be 4.7626 Hz.

The railway track system is the platform by which loads from moving trains are transferred to the underlying soil or supporting infrastructure such as bridges. The most common type of railway track system is ballasted track, which has been in use for over a century. Ballasted track has proved versatile. It can be constructed using locally available materials and with modifications to the rails and sleepers, crossings transferring trains from one route to another can be created. The structure of a ballasted track system consists of two main parts. The upper portion, termed the superstructure, comprises the rails, fastenings and sleepers. It is formed of components whose shape, stiffness and strength are designed and closely controlled. Below the superstructure is the substructure, which comprises the ballast and sub-ballast. Although the materials used in the substructure may have been specified, their engineering properties and geometric placement are less well controlled. In this chapter, we will explore how a typical ballasted track system transfers load to the ground and the ways in which the track form deteriorates, requiring maintenance and eventually renewal.

In this paper, a high-frequency radar test system was used to collect the data of clean ballast bed and fouled ballast bed of ballasted tracks, respectively, for a quantitative evaluation of the condition of railway ballast bed.

Based on original radar signals, the time–frequency characteristics of radar signals were analyzed, five ballast bed condition characteristic indexes were proposed, including the frequency domain integral area, scanning area, number of intersections with the time axis, number of time-domain inflection points and amplitude envelope obtained by Hilbert transform, and the effectiveness and sensitivity of the indexes were analyzed.

The thickness of ballast bed tested at the sleep bottom by high-frequency radar is up to 55 cm, which meets the requirements of ballast bed detection. Compared with clean ballast bed, the values of the five indexes of fouled ballast bed are larger, and the five indexes could effectively show the condition of the ballast bed. The computational efficiency of amplitude envelope obtained by Hilbert transform is 140 s·km⁻¹, and the computational efficiency of other indexes is 5 s·km⁻¹. The amplitude envelopes obtained by Hilbert transform in the subgrade sections and tunnel sections are the most sensitive, followed by scanning area. The number of intersections with the time axis in the bridge sections was the most sensitive, followed by the scanning area. The scanning area can adapt to different substructures such as subgrade, bridges and tunnels, with high comprehensive sensitivity.

The research can provide appropriate characteristic indexes from the high-frequency radar original signal to quantitatively evaluate ballast bed condition under different substructures.

The car body stiffness of express freight sliding side covered wagon decreased for the sliding and the resonance vibration based on the flexible car body has affected the dynamics performances. Dynamic loading will cause fatigue cracks and eventually lead to fatigue failure of the car body. This paper aims to investigate the influence of car body flexibility on the evaluation of the failure.

In this paper, the railway vehicles random analysis procedure (RVRAP) is employed to study the fatigue failure of the rigid-flexibility model. Following the analysis process, the rigid-flexibility model is established and four contrastive schemes for simulation analysis are designed. To verify the results, an experimental test using the real car body structure on the vibration test plant is carried out; the RMS of dynamic stress is obtained and compared with the simulation results.

The results show that the flexibility of the car body has a crucial influence on the fatigue life.

The reliability is verified regarding the use of RVRAP at an appropriate stage on the antifatigue design of the vehicle.

Rede Alta Velocidade, SA (RAVE), the state-owned company responsible for planning and developing a major high-speed rail project in Portugal, must persuade both public officials and lenders that the project is worth undertaking. It must also make a recommendation on the appropriate organizational form for the enterprise. Specifically, it must determine the role of the Portuguese government in financing and operating the high-speed rail network, with options ranging from full development and management of the project by the public sector to completely private development and management. Lying in between these two polar cases were a variety of hybrid models, often referred to as public-private partnerships (PPPs). Using data in the case, students have the opportunity to perform a benefit-cost analysis of the project. They also must think carefully about the optimal role of the government in a major new infrastructure project.

After analyzing and discussing the case, students will be able to:

• Understand the nature of a global public good

• Perform a back-of-the-envelope benefit-cost analysis of polio eradication

• Discuss the appropriate strategy for eradicating an infectious disease

• Apply game theory to analyzing which countries would be likely to contribute funds toward global polio eradication

• Discuss the role of private organizations in the provision of global public goods

Understand the nature of a global public good

Perform a back-of-the-envelope benefit-cost analysis of polio eradication

Discuss the appropriate strategy for eradicating an infectious disease

Apply game theory to analyzing which countries would be likely to contribute funds toward global polio eradication

Discuss the role of private organizations in the provision of global public goods

Risk analysis has come to be seen as a quantitative process in which risks are measured by the use of probabilities. However, since every new project is essentially unique with no previous data on it, decisions taken as to the nature of the risks are highly subjective and the actions that may be carried out to mitigate the effects of these risks are not clear‐cut; a non‐numerical approach can, therefore, be more useful. The risk management approach detailed here identifies the risks, checks for dependence amongst risks, and assesses the likelihood of occurrence of each risk by using linguistic variables through the medium of fuzzy sets. The use of linguistic variables is a departure from conventional risk analysis methods that rely rather heavily on statistical analysis to quantify the effects of risks on projects. The entire risk management process is explained, and a case study is carried out to demonstrate the use of the ideas treated. The case study concentrates on the activities of the substructure in a multi‐storey building project. The ten largest risks are identified, and dependence among them is assessed through fuzzy set calculations. The assessment of risk dependencies brings about a reduction in the total number of risks analysed, as highly dependent risks are treated together, and the use of linguistic variables brings about a non‐numeric approach to risk analysis with which project managers can be comfortable. The risk management process, through the use of fuzzy sets, is better able to handle project management knowledge on risk analysis which is highly subjective, and varies from project to project.

The purpose of this paper is to apply a spatial approach to organizational inequality to explore why unequal opportunity structures persist in an organization despite its commitment to diversity and employing highly skilled ethnic minority employees.

The (re)production of inequality is explored by linking research on organizational space with HRM diversity management. Data from an ethnographic study undertaken in a Danish municipal center illustrates how a substructure of inequality is spatially upheld alongside a formal diversity policy. Archer’s distinction between structure and agency informs the analysis of how minority agency not only reproduces but also challenges organizational opportunity structures.

The analysis demonstrates how substructures of inequality stabilize in spatial routines enacted in an ethnic zoning of the workplace and ethnification of job categories. However, the same spatial structures allows for a variety of opposition and conciliation strategies among minority employees, even though the latter tend to prevail in a reproduction rather than a transformation of the organizational opportunity structures.

The reliance on a single case study restricts the generalizability of the findings but highlights fruitful areas for future research.

The study sensitizes HRM practitioners to the situated quality of workplace diversity and to develop a broader scope of HRM practices to address the more subtle, spatially embedded forms of inequality.

Theoretical and empirical connections between research on organizational space and HRM diversity management have thus far not been systematically studied. This combination might advance knowledge on the persistence of micro-inequality even in organizations formally committed to diversity.

Limited funding to maintain and preserve short‐line railroad (SLRR) bridge infrastructure requires that important priority decisions be made on an annual basis. The compartmentalized, dispersed, and diverse nature of many SLRR owners and operators is such that there is a need for a coordinated and centralized effort to evaluate the state‐wide system as a whole, to ensure the most effective overall resource allocation and also identify assets that either outperform predictions or consume disproportionate levels of resources for maintenance and operation, allowing for review of design and construction practices. The purpose of this paper is to examine the state of the art for railroad bridge population management and resource allocation decisions and to develop a state‐wide SLRR bridge prioritization methodology, to be used as a tool by a state agency to assist in allocating limited public funding for bridge maintenance, rehabilitation and replacement activities.

A literature review examining the state of the art of railroad bridge population management and resource allocation decisions was conducted, which provided the foundation for the development of a bridge prioritization algorithm. A state‐wide survey was conducted to develop a bridge database. A detailed evaluation of a statistically significant sample of bridges was conducted, to determine the structural and maintenance needs and preservation status of sub‐populations. The research team developed methodologies, applicable to the entire population, to develop a ranking of bridge preservation candidates.

A risk‐based prioritization algorithm is proposed to assign a relative risk score to each bridge in the population. The algorithm provides a management tool for making more effective maintenance and preservation decisions. Additionally, the bridge database allows managers to examine sub‐populations according to structural parameters to evaluate performance.

The revisable, modular framework of the prioritization algorithm provides a simple, effective and versatile tool for asset management and evaluation. The present proposal of this new prioritization methodology for SLRR bridges is a valuable tool for agencies faced with making rational decisions with limited information. Such a methodology does not currently exist in the literature and is of significant interest to short‐line owners/operators and state transportation agencies.