AbstractResearch on track quality behavior has been extensively published, and many different approaches have been presented to describe the process of track quality. The research goal of this paper ...is to form a basis for a data-driven tamping prediction based on track quality analyses over time. A research database containing asset information, executed maintenance tasks, and measuring data of some 4,400 km of track of the Austrian rail network in a time sequence of 16 years is available. The modified standard deviation of vertical track geometry is identified as an ideal track quality indicator for planning and predicting tamping tasks in Austria in the context of this research. Further analyses show that a linear regression function is best suited for describing track quality between two tamping tasks and shows the best accuracy for predicting track quality in the future. An algorithm was developed by means of the linear regression function that enables analyses of track quality behavior over time for long time series and the whole network. This includes track quality before and after tamping tasks as well as deterioration rates. In the future, these basics have to be combined with further technical evaluations to detect an optimal intervention limit. Furthermore, economical and operational considerations must be incorporated to find the optimal tamping strategy under the given conditions.
The cutting-edge engineering maintenance software systems of various objects are aimed at processing of geo-location data coming from the employees’ mobile devices in real time. To reduce the amount ...of transmitted data such systems, usually, use various filtration methods of geo-coordinates recorded directly on mobile devices.The paper identifies the reasons for errors of geo-data coming from different sources, and proposes an adaptive dynamic method to filter geo-location data. Compared with the static method previously described in the literature 1 the approach offers to align adaptively the filtering threshold with changing characteristics of coordinates from many sources of geo-location data.To evaluate the efficiency of the developed filter method have been involved about 400 thousand points, representing motion paths of different type (on foot, by car and high-speed train) and parking (indoors, outdoors, near high-rise buildings) to take data from different mobile devices. Analysis of results has shown that the benefits of the proposed method are the more precise location of long parking (up to 6 hours) and coordinates when user is in motion, the capability to provide steam-oriented filtering of data from different sources that allows to use the approach in geo-information systems, providing continuous monitoring of the location in streamoriented data processing in real time. The disadvantage is a little bit more computational complexity and increasing amount of points of the final track as compared to other filtration techniques.In general, the developed approach enables a significant quality improvement of displayed paths of moving mobile objects.
A probabilistic Track Performance Index (TPI) is proposed for maintenance prioritization in the railways. TPI evaluates the safety condition in a segment by estimating the derailment probabilities on ...curves as the track condition representatives. Via Reliability analysing methods and considering track geometry and irregularities, vehicle characteristics, and speed, derailment probability for a segment of the track can be estimated as its TPI. For comparing the performance of different blocks, the higher the TPI, the more critical the safety situation. The method is illustrated through three case studies, and the comparisons between the TPI and deterministic Track Quality Index (TQI) indicate that the probabilistic TPI identifies curves with a high risk of failure that TQI fails to detect. The results indicate applying TQI solely is biased, and TPI can overcome this shortage. Hence, it is suggested that TPI should be used alongside TQI as a complement for more reliable maintenance planning.
Adequate railway track condition is a prerequisite for safe and reliable railway operation. Many track quality indices (TQIs) have been developed with the aim of assessing the track condition ...holistically. These indices combine measurement signals of some or all relevant geometry parameters with different mathematical models. In this paper, a selection of important TQIs is evaluated. Using measurement data of a five kilometer track section, the indices are calculated and their properties are discussed. This study reveals that all indices exhibit drawbacks to varying degrees. As a consequence, a new index has been developed—the track quality index of Graz University of Technology (TUG_TQI). Its favorable characteristics are presented by means of the above-mentioned test section. The TUG_TQI combines all relevant track geometry parameters, which are normalized beforehand to eliminate over or underrepresentation of different parameters. Thus, the index reliably describes the overall geometrical track quality.
Track geometry parameters from rail track inspection are regulated within unique safety limits for different track classes. This study focuses on developing an index that combines safety and track ...quality because of the inefficiency of corrective maintenance activities between routine maintenance cycles when federal geometry limits are violated. This combination is achievable by summarizing multivariate track geometry parameters as an improvement to previous linear approaches to address the problem of inefficient track geometry maintenance programs. The use of nonlinear dimension reduction (T-stochastic neighbor embedding (T-SNE)) for hybrid track quality index development and the influence of time-based parameters on track quality is evaluated in this study. The results show that the probability of geometry defects is correlated with principal components, but T-SNE had the best prediction on train-test splits despite its poor performance on a blind validation set. The absence of an observable correlation between the track geometry and acceleration data requires further investigation.
The time interval of the observational data changes irregularly because of the difference of sensors' sampling rate, the communication delay and the target leaving observation region of the sensor ...sometimes. These problems of asynchronous observation data greatly reduce the tracking accuracy of the multi-sensors system. Therefore, asynchronous data fusion system is more practical than synchronous data fusion system, and worthier of study. By establishing an asynchronous track fusion model with irregular time interval of observation data and combining with the Track Quality with Multiple Model (TQMM), an asynchronous track fusion algorithm with information feedback is proposed, and the TQMM is used for weight allocation to improve the performance of the asynchronous multi-sensor fusion system. The simulation result shows that the algorithm has better tracking performance compared with other algorithms, so that this kind of problem of track-to-track fusion for asynchronous sensors is solved effectively.
Today’s railway transport is built upon high-performance infrastructure. Cost-effective yet sustainable infrastructure presumes tracks with a precise and durable geometry. At ballasted tracks, the ...geometry is created and restored through tamping machines, which position the track panel and compact the ballast beneath the sleepers. It is commonly agreed that the ballast compaction plays an important role in the long-term stability of the track. Yet, there is no method available which allows a direct correlation between the compactness of the ballast and the stability of the track geometry. Available studies either model track behaviour without considering the bedding, or analyse ballast compactness locally while disregarding its influence on the track geometry. This paper presents a new methodology which establishes a relation between these two topics—ballast compaction during tamping and subsequent track behaviour. A state-of-the-art tamping machine has been equipped with an experimental measurement setup, constantly recording relevant data during every tamping process. These data can be used to derive an indication for the achieved compaction under every sleeper. Utilising the tamping machine’s internal measuring system for track geometry documentation, every tamping process (every sleeper) is assigned to the precise position along the track. The data set is merged and synchronised with regular track geometry measurements of the infrastructure manager. The result is a comprehensive data set which allows precise analyses between tamping machine measurements and track behaviour. This data set provides the foundation for future research, aiming towards a better understanding of the tamping process and its influence on the quality and durability of the established track geometry.
Effective forecasting of track irregularity development trend is critical to the railway maintenance and management. In China, track irregularity is commonly evaluated via an index called track ...quality index (TQI). According to the trend and random of the TQI development, a hybrid forecasting method composed of the improved grey model (GM(1,1)) and a particle swarm optimization support vector machine (PSO-SVM) is proposed in this paper. First, a non-equal interval sequence is transformed into an equal interval sequence, and an improved GM(1,1) based on the compound trapezoid quadrature formula is proposed to estimate the short-term rough trend of the TQI. Then, PSO-SVM is adopted to correct the rough results and obtain an accurate TQI trend. Numerical experiment results show that the proposed forecast method outperforms the track irregularity trend component and the grey nonlinear periodic correction method and the non-equal interval weighted grey model and neural networks in terms of relative error.
A joint target detection and tracking method based on plot-track quality evaluation (PTQE-D&T) is proposed here. The presented method consists of three consecutive steps. First, a set of candidate ...plots is extracted from the Detector and Plot-Extractor, where the plot quality is calculated simultaneously based on multi-dimensional echoes constituting the plot. Then, a track-before-detect (TBD) processor based on dynamic programming (DP) is utilised to jointly elaborate the observations from multiple scans and outputs potential tracks to be confirmed. Finally, a confirmation strategy is introduced via plot-track quality evaluation. Experimental results are provided to demonstrate the effectiveness of the proposed method, where two data sets collected from a ground-based surface-search radar and a ship borne 3D radar are used. Moreover, the proposed PTQE-D&T structure is totally consistent with conventional radar data processing architecture, meaning that it is promising in engineering applications.
The positive effects of under sleeper pads have already been proven by track and laboratory tests worldwide. In Austria, padded concrete sleepers reduce track deterioration by 50 percent and have ...therefore been used as standard components since 2010. As the pads increase material costs, many infrastructure managers have discussed the idea of covering costs by reducing the ballast bed thickness. Technically, this approach (less ballast) is feasible, as the pads increase the track elasticity and protect the ballast. Further, pads lead to higher rail deflection and distribution of the load to more sleepers, and the stresses in sleepers are therefore relieved. Here, we compared Austrian test sections with padded and unpadded concrete sleepers and with a difference in the ballast bed thickness: standard thickness of 30 cm against 20 cm below the sleeper. Fractal analyses and standard deviations of the track’s longitudinal level provided information about the sections’ long-term track behaviour over 20 years. We found that the standard solution with 30 cm ballast performed better in the long term compared to 20 cm. Additionally, the test section with padded sleepers on a reduced ballast bed thickness showed a lower maintenance demand than the unpadded concrete sleeper track on a 30 cm ballast bed.
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