The paper focuses on a method to synthesize the track vertical irregularities, with the possibility of application in the simulation of the dynamics in the railway vehicles. The basic elements of the ...method are the power spectral density of the track irregularities and the quantities describing the track geometry quality, as they have been adopted in compliance with the ORE B 176 report and UIC 518 leaflet. A major contribution of this method is the extension of the interval specific to the wavelength of the track vertical irregularities, so that this interval be representative for the frequency range of the vertical vibrations in the railway vehicle. The results of the numerical simulations of the dynamic behavior in a vehicle while running on a tangent track with vertical irregularities being synthesized as above demonstrate its efficiency.
AbstractAlthough reliability centered maintenance (RCM) has been used widely in the maintenance and renewal (M&R) of railway infrastructures, M&R methods and maintenance frequencies still require ...considerable study to obtain information on optimum decisions. Recently, various attempts have been made to optimize the maintenance works in railway engineering, although a decision support system on selecting the maintenance or renewal works has not been suggested distinctly. Therefore, a genetic algorithm on the basis of the nondominated sorting method (NSGA) was used in this study to optimize the biobjective functions on M&R interventions and costs. The results showed that the optimum frequency of M&R could be determined using the NSGA method with various constraints. Moreover, field application of the suggested method also was considered. Future work will be concentrated on the systematic approach of the decision support model with RCM and the enterprise resource planning (ERP) system of the infrastructure manager (IM).
This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to ...know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximise the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary. In particular, the parameters related both to the track quality and to the rolling contact were considered in this study. With this aim, a sensitivity analysis was performed to assess their influence on the vehicle dynamic behaviour. To do this, 72 dynamic simulations were performed modifying, one at a time, the track quality, the wheel-rail friction coefficient and the equivalent conicity of both new and worn wheels. Three values were assigned to each parameter, and two wear states were considered for each type of wheel, one for new wheels and another one for reprofiled wheels. After processing the results of these simulations, it was concluded that all the parameters considered show very high influence, though the friction coefficient shows the highest influence. Therefore, it is recommended to undertake any future simulation job with measured track geometry and track irregularities, measured wheel profiles and normative values of the wheel-rail friction coefficient.
With the rapid development of construction of railway in China, forecast of track irregularity becomes more significance for more efficient maintenance works. The piecewise linear prediction model is ...established under the conditions of known tamping operation efficiency and initial quality of railway track. The changing trend of track irregularity between two tamping operations. So in this paper, a piecewise linear representation based forecasting method is proposed to predict the track irregularity by mining the Track Quality Index (TQI) with underlying "memory" of track changing information of its special characteristic. Experiment results demonstrate that the accuracy of the proposed prediction model is over 94%, which can be used as important reference for arranging maintenance works.
The integrated particle filter (IPF) is an algorithm for single-target tracking in clutter, which incorporates the probability of target existence (PTE) into the traditional particle filter as a ...track quality measure for false track discrimination (FTD). This study investigates two IPF-based fixed-interval smoothing algorithms: the IP smoothing (IPS) algorithm and the IP-Rauch–Tung–Striebel backward smoothing (IP-RTSBS) algorithm, both of which are capable of trajectory estimation and FTD. The IPS algorithm fuses the propagations for each pair of forward IPF and backward IPF particles to obtain the smoothing propagation that is used to update the track state by applying all available measurements in the current scan. The IP-RTSBS algorithm employs the forward filtering backward smoothing approach to smooth the trajectory state, which is then applied to the RTS smoothing methodology to obtain the smoothing propagation used to update the PTE. As a result, both FTD and trajectory estimation are improved. The smoothing benefits of the two algorithms are validated in the simulations, where a sliding batch mode with overlapping measurements is utilised to limit the smoothing lag.
Rail transport, in competition with other modes of transport, has to improve the quality of passenger and freight transport. In order to carry passengers and goods quickly, efficiently and safely, it ...is necessary take maintenance railways so that their geometric parameters do not exceed the tolerances. About real railway track condition, the data is obtained by track geometry recording car, measuring seven geometric parameters dispersion. This paper presents the methodology for determining and estimating the geometric parameters of the track geometry, which shows that the track quality index (TQI) is the sum of the variance of seven geometric parameters. Experimental research on the two-track A (8km) and B (11km) a three-year period (2015-2017) for all 12-month KKI, establish their quality dynamics (change over time). These data indicate that the quality of the analyzed sections A and B was good, but due to the increasing mass (in megatons) of transported loads, there is a tendency to deteriorate.
Santrauka
Geležinkelių transportas, konkuruodamas su kitomis transporto rūšimis, privalo gerinti keleivių ir krovinių vežimų kokybę. Norint greitai, efektyviai ir saugiai vežti keleivius ir krovinius, būtina taip prižiūrėti geležinkelių kelius, kad jų geometrinių parametrų nuokrypiai neviršytų leidžiamųjų nuokrypių. Apie tikrąją geležinkelių kelio būklę duomenys gaunami kelmačiu išmatavus septynių geometrinių parametrų sklaidą. Šiame darbe pateikta geležinkelio kelio geometrinių parametrų sklaidos nustatymo ir vertinimo metodika, kurioje įrodyta, kad kelio kokybės indeksas (KKI) yra septynių geometrinių parametrų dispersijų suma. Eksperimentiškai ištyrus dviejų geležinkelio kelių A (8 km) ir B (11 km) trijų metų laikotarpiu (nuo 2015 iki 2017 metų) visų 12 mėnesių KKI, nustatyta jų kokybės dinamika (kaita bėgant laikui). Šie duomenys rodo, kad ištyrinėtų A ir B ruožų kelio kokybė buvo gera, bet dėl didėjančios pervežtų krovinių suminės masės (megatonų skaičiaus) turi tendenciją blogėti.
Abstract
The influence of rail cant on the overall geometry conditions of railway tracks is assessed both theoretically and experimentally in this study. Extensive data obtained from a light railway ...line are used for experimental investigations. Modelling of rail—wheel contact using the ADAMS/Rail program is undertaken for theoretical investigations. The need to incorporate rail cant into the development of the track geometry indices is identified, and a method of performing this is proposed. Using this approach, a new track index is defined, for which the main geometry parameters, including alignment, profile, track twist, track gauge, and rail cant (rail twist), are considered. For the development of the new track index, these parameters are combined, assigning justified coefficients to each geometry parameter according to its contribution to the overall conditions of the track. The research methodology and the results are discussed. A practical use of the new index is presented to indicate its capability and applicability.
In this study a joint maximum likelihood （JML） algorithm was developed to solve problems re- garding interdependent and contradictory relationships between track correlation and sensor bias ...estimation in multi-sensor information fusion systems. First, the relationships between track correlation and sensor bias estimation of a multi-sensor system were analyzed. Then, based on these relationships, a JML function of the track correlation and sensor bias estimation was developed, while an iterative two-step optimization procedure was adopted to solve the JML function. In addition, transformation of sensor bias from Cartesian coordinates to polar coordinates and a complete design of track quality and ambiguity processing were provided. Finally, several Monte Carlo simulations were built to test the effect of target density and different sensor bias in the JML algorithm. Simulation results showed that the JML algorithm presented in this paper had a higher correct correlation rate and more accurate sensor bias estimation than traditional methods, demonstrating that the JML algorithm had good performance.
Due to the impact of train load, temperature force and foundation deformation, high-speed railway track disease becomes more and more serious. The existing track maintenance mode can't meet the ...requirement of the modern tack structure. Track quality state and its evaluation ways was analyzed, and a method to predict track maintenance cycle based on the track quality deterioration rule was put forward. The track maintenance cycle could be forecasted scientifically by TQI deterioration rule, which is of great significance to high-speed railway maintenance in the future.
This paper investigates track vibration energy as a potential novel indicator of turnout’s track quality. Exploiting measurements of train-induced track vertical accelerations at different sections ...of a turnout, the track vibration energy is estimated and its variation over time analysed through the creation of statistical empirical distributions. A clear increase in vibration energy can be observed over a period of two years. An analysis of the turnout track geometry through a standard indicator adopted by the railway industry is then performed, and an increase in longitudinal level over the same investigation period clearly indicates track degradation due to cumulative loading. Last, a correlation analysis is performed between the estimated vibration energy and the indicator of track quality based on geometry data. Such analysis shows a significant correlation between the two indexes, thereby addressing the possibility of developing a novel condition monitoring tool for track quality based on track vibration energy. The whole investigation is based on full-scale measurements of track vertical acceleration and track geometry performed over a period of two years in a turnout of the Danish railway infrastructure.
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