•Railway track degradation in transition zones by ballast wear and breakage.•Vibration experiments with impact hammer and train passage validating a FEM.•Developed linear dynamic FEM can use ...investigating the effect of USP.
To meet the increasing demands and be competitive in the market, railway systems must be sustainable. One of the important criteria for sustainability is to have lower life cycle costs (LCC). Several statistics report higher track geometry degradation in transition zones, and maintenance of these zones has a large share in LCC. One of the reasons behind the accelerated track degradation is the wear and the breakage of ballast in transition zones due to sudden stiffness changes and ballast vibrations. Optimized track support solutions can have a positive impact on track degradation in transition zones. Under sleeper pads (USP) as supporting elastic elements are being used to decrease stress and vibration on the ballast. In this study, numerical models with and without USP components are built for the selected transition zone. Numerical models simulate dynamic load from train passages and impact hammer load. Thus, the USP component effect on vibrational behavior of the track is analyzed. For the validation of simulations, several experiments were carried out on the selected transition zone. In addition to them, vibration mitigation experiments were performed. According to the simulation and experimental outcomes of the study, the developed models are satisfactorily in compliance with experimental results. It has been observed from simulation results that the integration of the USP component into track provides an approximately 25% decrease in ballast acceleration. On the other hand, it has a negative effect on rail and sleepers by increasing their vibration. Since this is an expected outcome of USP, the methodology in the study can be beneficial in the design phase.
•We introduced the development of CR express in China since its birth in 2011 under the Belt and Road Initiatives.•We analysed and compared the fees structures of 5 typical CR express routes and ...related seaborne container shipping routes.•We compared the hinterland patterns of 5 CR express routes under two scenarios with discrete choice theory.
To analyse the hinterland patterns of the CHINA RAILWAY Express (CR express) in China under the Belt and Road Initiative, this paper first reviews the development stages of the CR express. Second, 5 typical CR express routes are examined to comparatively analyse the CR express and seaborne container shipping from the perspective of freight cost structure. According to the binary logit model, the current and the prospective hinterland patterns (choice probability) of two types of products of the CR express are explored. The results show that governmental subsidies for the operators of CR express contribute to decreasing 60% of CR express freight cost. And shippers of IT products are easier to choose the CR express than those of other products. As a result, Chongqing, Chengdu, Zhengzhou and Wuhan have the same opportunities to become the regional railway hub for IT product transport. In Chongqing, however, the high share of other products in CR express market will impact greatly on its competition for the regional railway hub among the aforementioned inland cities.
A practical condition monitoring method is proposed for the fault diagnosis of railway point machines (RPMs) by considering the difficulty of obtaining in-field failure data. Failures in RPMs have a ...significant effect on railway train operations, and it is very crucial to detect abnormal conditions in RPMs. However, it is generally difficult to obtain in-field failure data for a classifier training step. A diagnosis method using dynamic time warping is proposed to manage the variation in durations of RPM movement without a training step. On the basis of the experimental results with RPMs operated in Korea, it is believed that the proposed method without a training step can detect abnormal electric-current shapes more accurately than previous training-based methods.
The notions of labour, mobility and piety have a complex and intertwined relationship. Using ethnographic methods and a historical perspective, Temple Tracks critically outlines the interlink of ...railway construction in colonial and post-colonial Asia, as well as the anthropology of infrastructure and transnational mobilities with religion. In Malaysia and Singapore, evidence of religion-making and railway-building from a colonial past is visible in multiple modes and media as memories, recollections and 'traces'.
The assessment of the power quality (PQ) could be a valuable tool to foster the efficiency of the railway systems. PQ is a well-addressed topic in conventional ac 50/60 Hz power systems, and many ...procedures, algorithms and measurement systems were presented in the international standards and widely discussed in the scientific literature. A less explored research field is the assessment of the PQ in the railway traction supply systems, in particular with reference to the dc and 16.7 Hz systems. The article explores this theme, proposing an extension of the definitions and of the standard measurement procedures for some of the main PQ indexes, well defined and widely used for conventional power systems, in order to be used also in all railway traction supply systems. The limits or difficulties of applicability are discussed with reference to measurements performed both on-board and in substation. The proposed procedures are applied to an experimental case of a real dc railway system with a large measurement campaign.
Along with the rapid expansion of urban rail networks comes the need for accurate predictions of railway induced vibration levels at grade and in buildings. Current computational methods for making ...predictions of railway induced ground vibration rely on simplifying modelling assumptions and require detailed parameter inputs, which lead to high levels of uncertainty. It is possible to mitigate against these issues using a combination of field measurements and state-of-the-art numerical methods, known as a hybrid model. In this paper, two hybrid models are developed, based on the use of separate source and propagation terms that are quantified using in situ measurements or modelling results. These models are implemented using term definitions proposed by the Federal Railroad Administration and assessed using the specific illustration of a surface railway. It is shown that the limitations of numerical and empirical methods can be addressed in a hybrid procedure without compromising prediction accuracy.
► Introduction of a new safety maturity model and safety maturity index. ► Relationship between precursors, top events, injuries and deaths on metro premises. ► The higher the maturity index the less ...the number of the registered injuries. ► No correlation between the maturity index and precursors, top events or fatalities. ► Best practices to improve metros safety in each precursor category is introduced.
Fatalities due to railway accidents occur rarely and some railways identify risks from potential accident precursors. By lowering precursor frequency, the probability of more serious incidents and accidents may be reduced, following the idea of a reverse pyramid between precursors, top events, injuries and deaths. To assist in reducing such risks, a new safety maturity model (SMM) is proposed which aims to address not only the behavioural and/or attitudinal culture, but also technical, operational and methodological elements and actual achievements in terms of safety outcomes.
This paper outlines the results of precursor analysis from 18 CoMET and Nova railways, all but two of which are metro (subway) operations1Metro railways are urban passenger electric railways with a significant proportion of grade separated (underground or elevated) track and relatively close station spacing. The two commuter routes have longer station spacing and more surface track than most metros.1, the other two being commuter railways. One of the commuter railways has mixed traffic including freight and long distance passenger trains, while four of the metro railways share lines with longer distance railways.
The paper analyses precursors, top events, injuries and deaths as well as safety maturity and their relationships both to each other and to incidents and accidents for the set of the major global metro railways. The 27 precursors analysed, for the period 2002–2009, fall into six categories: human performance; technical failures; passengers: fires; malicious action and management action.
To assess safety maturity, a model was developed based upon literature and metro experience. A questionnaire assessed the following safety maturity criteria for each metro: publication of safety reports; periodicity of safety monitoring; prioritisation of safety related incidents; efforts to mitigate risks and avoid incidents; description of safety procedures and monitoring of residual risks. The responses of each metro were scored to determine its aggregate safety maturity level.
Statistical analysis indicates a positive correlation between injuries and top events as well as between injuries and precursors. The safety maturity score is correlated with injuries but not with precursors, top events or fatalities. Using these results, this paper proposes a number of measures to improve metro railways safety in each precursor category.
•Characteristics of factors and consequences of railway incidents are discussed.•Network diagrams are constructed to indicate the topological structure of incidents.•Complex interdependencies and ...cascading among factors and effects are captured.•Associations and sequences of the network's change mechanisms are explained.•Real railway incident data is used to illustrate the network analytical framework.
Railway networks are a critical infrastructure in today's society, and many efforts have been made to promote their safety. Even when safety measures are introduced, railway incidents still occur. Incident investigation can acquire facts about the causation factors and effects of incidents. In this study, we propose a network analytical framework to identify the factors and effects of railway incidents. This framework captures the complexity of interdependencies and delineates the causation of railway incidents in incident chains; the incident chains are then remodeled to study the topological characteristics of factors and effects in a network model. Reported railway incident cases in Japan are selected for analysis from three perspectives: local view analysis, global view analysis, and contextual view analysis. Statistics and network diagrams are developed from each perspective to analyze the relational railway incident data. The results show that most railway incidents are caused by more than one factor, and one factor tends to cascade into others. Each factor has its own role in the occurrence of an effect, but interdependencies can still be found among most factors. The significant factors in railway incidents are revealed in this study, and it is suggested that tackling the occurrence of the significant factors and their interdependent factors is effective for controlling and reducing the occurrence of railway incidents. The network analytical framework can be used to forward estimate the effect specifically caused by a factor and its propagation exposure, as well as to backward determine the possible causes of an effect from its interdependent intermediates and factors.
•The joint optimization model of railway pricing and seat allocation is non-concave and non-linear.•This study proposes linearization and relaxation techniques in order to find the optimal ...solution.•The proposed model and algorithm are illustrated on a real-world railway network.
This paper examines optimal pricing and seat allocation schemes in passenger railway systems, where ticket pricing and seat allocation (or capacity allocation) are both Origin-Destination specific. We consider that the demand is sensitive to the ticket price, and a non-concave and non-linear mixed integer optimization model is then formulated for the ticket pricing and seat allocation problem to maximize the railway ticket revenue. To find the optimal solution of the ticket revenue maximization problem effectively, the proposed non-concave and non-linear model is reformulated such that the objective function and constraints are linear with respect to the decision variables or the logarithms of the decision variables. The linearized model is then further relaxed as a mixed-integer programing problem (MILP). Based on the above linearization and relaxation techniques, a globally optimal solution can be obtained by iteratively solving the relaxed MILP and adopting the range reduction scheme. Two numerical examples are presented for illustration.
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