Browsing by Author "Gerber, Ulf"

Now showing 1 - 13 of 13
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    Common Crossing Condition Monitoring with on-Board Inertial Measurements
    (Czech Technical University, Prague, 2019) Sysyn, Mykola; Nabochenko, Olga; Gerber, Ulf; Kovalchuk, Vitalii V.; Petrenko, Oleksiy
    EN: A railway turnout is an element of the railway infrastructure that influences the reliability of a railway traffic operation the most. The growing necessity for the reliability and availability in the railway transportation promotes a wide use of condition monitoring systems. These systems are typically based on the measurement of the dynamic response during operation. The inertial dynamic response measurement with on-board systems is the simplest and reliable way of monitoring the railway infrastructure. However, the new possibilities of condition monitoring are faced with new challenges of the measured information utilization. The paper deals with the condition monitoring of the most critical part of turnouts - the common crossing. The application of an on-board inertial measurement system ESAH-F for a crossing condition monitoring is presented and explained. The inertial measurements are characterized with the low correlation of maximal vertical accelerations to the lifetime. The data mining approach is used to recover the latent relations in the measurement’s information. An additional time domain and spectral feature sets are extracted from axle-box acceleration signals. The popular spectral kurtosis features are used additionally to the wavelet ones. The feature monotonicity ranking is carried out to select the most suited features for the condition indicator. The most significant features are fused in a one condition indicator with a principal component analysis. The proposed condition indicator delivers an almost two-time higher correlation to the lifetime as the maximal vertical accelerations. The regression analysis of the indicator to the lifetime with an exponential fit proves its good applicability for the crossing residual useful life prognosis.
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    Common Crossing Fault Prediction with Track Based Inertial Measurements: Statistical vs. Mechanical Approach
    (Akadémiai Kiadó, Hungary, 2019) Sysyn, Mykola; Gerber, Ulf; Nabochenko, Olga; Kovalchuk, Vitalii V.
    EN: The analysis of track based inertial measurements for common crossing fault detection and prediction is presented in the paper. The measurement of spatial acceleration in common crossing spike and impact position during overall lifecycle are studied regarding to rolling surface fatigue degradation. Two approaches for retrieving the relation of inertial parameters to common crossing lifetime are proposed. The first one is based on the statistical learning method - t-SNE algorithm that helps to find out similarities in measured dataset. The second one is a mechanical approach that handles the data with a fatigue and contact models. Both approaches allow the significant improvement of the common crossing fault detection as well as its early prediction.
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    Comparison of the Effects and Efficiency of Vertical and Side Tamping Methods for Ballasted Railway Tracks
    (Elsevier Ltd, 2022) Przybyłowicz, Michał; Sysyn, Mykola; Gerber, Ulf; Kovalchuk, Vitalii V.; Fischer, Szabolcs
    EN: The relatively high maintenance costs of the ballast track are related to the short lifecycle of the ballast layer. The current vertical ballast tamping technology (e.g., Plasser & Theurer, Matisa, etc.) causes high ballast destruction and is neither applicable for unconventional sleepers’ designs nor slab tracks. The side tamping method presents an alternative, ballast saving, and sleeper form independent ballast tamping technology. This paper compares the ballast layer compaction and its resistance to permanent settlements accumulation after the vertical and the side tamping methodologies. Scaled models of ballast layer and tamping units and scaled simulation with discrete element method (DEM) were applied for the comparison. In the laboratory tests, the ballast compaction along the sleeper was estimated using the measurements of elastic wave propagation. The settlements resistance for both tamping methods was estimated under the vibration loading. The tests’ results show 5–7% higher compactness of the ballast layer under the sleeper ends for the side tamping method. The settlement intensity of the ballast layer after the vertical tamping is higher than for the side tamping method. In discrete element modeling, the performed laboratory tests were simulated. The compactness of the ballast bed, as well as the residual stresses, were determined in MATLAB. The side tamping technology provided five times higher residual stresses in the ballast layer below the sleeper than in the case of vertical tamping, which can be explained by the more stable and dense layer resulting from the side tamping ensures higher interlocking between the grains. The simulation of the wave propagation shows an influence of the residual stresses on the wave propagation velocities. The simulated wave propagation velocity was more than two times higher for the side tamping than for the vertical one.
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    The Complex Phenomenological Model for Prediction of Inhomogeneous Deformations of Railway Ballast Layer after Tamping Works
    (Warsaw University of Technology, Poland, 2018) Sysyn, Mykola P.; Gerber, Ulf; Kovalchuk, Vitalii V.; Nabochenko, Olga S.
    EN: The given article considers the method of calculating the track geometry deformation with respect to uneven accumulation of residual deformations along the track. The technique proposes two significant changes in existing approaches to calculating the efficiency of the ballast layer. The transition from the approach of allowable stresses design in the ballast layer to the deformative approach of accumulations of track geometry deformations allows us to draw conclusions regarding the intervals of track tamping and the duration of ballast layer life cycle. The transition from the determinative to probabilistic approaches makes it possible to draw conclusions not only from the average unevenness, but also with regard to all possible facts of unevenness. The method is based on the mechanism of sudden and gradual deformations occurrence, which depends on a number of key factors: dynamic stresses on the ballast, non-uniformity of track elasticity, performance of current maintenance work. Based on the experimental studies results, the dependencies of sudden deformations and the intensity of gradual deformations on the level of stress on the ballast layer were established. The experimental results of the influence of the sub-ballast base elasticity on the intensity of accumulation of residual deformations are shown. On the basis of the developed method, the prediction of track geometry deterioration for a given structure of the track, the rolling stock and the permissible level of geometric deviations for track maintenance is presented.
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    Evaluation of RailWay Ballast Layer Consolidation After Maintenance Works
    (Czech Technical University, Prague, 2019) Sysyn, Mykola P.; Nabochenko, Olga S.; Kovalchuk, Vitalii V.; Gerber, Ulf
    EN: Abstract. The results of the study of the ballast layer consolidation after the work of ballast-tamping machines of different types are given in the article. The existing methods of determining the degree of consolidation of the ballast layer are analysed. The seismic method was improved by means of a complex dynamic and kinematic interpretation of the impulse response. For the dynamic interpretation with the use of statistical analysis, the features are selected so that they correspond to the degree of consolidation of the ballast layer. On the basis of researches, a device and software were developed that allow an automated evaluation of the ballast layer consolidation based on the kinematic and dynamic analysis of the measured impulse response. The measurements of the degree of the ballast layer consolidation after an operation of ballast-consolidation machines in different sequences allowed establishing the efficiency of the consolidation and the feasibility of the machines’ application.
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    Experimental Investigation of the Influence of Train Velocity and Travel Direction on the Dynamic Behavior of Stiff Common Crossings
    (University of Niš, Serbia, 2019) Kovalchuk, Vitalii V.; Sysyn, Mykola P.; Gerber, Ulf; Nabochenko, Olga S.; Zarour, Jandab; Dehne, Stefan
    EN: Abstract. Common crossing rails are subjected to a rapid deterioration of the rolling surface due to a dynamic loading of trains. The present study is devoted to an experimental study of the displacement and rail strain measurements in the common crossing. The experimental measurements were carried out for two stiff common crossings under the dynamic loading of high-speed train for the velocity range of 54-254 km/h. The results showed 2.5 times increase of the maximal displacements within the velocity range. The absence of the difference in the displacements between the trailing and the facing travel direction is explained with the relative displacement measurements between the rail and the sleeper and the different dynamic impact loading for the wing rail. The proposed model-based analysis of the absolute measurement of rail strain enables us to estimate the dynamic factor under the impact loading. The wing rail for trailing direction is almost twice as highly loaded as the frog rail for the facing direction. The maximal dynamic factor for the trailing direction shows almost no change for the velocities of more than 200 km/h.
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    Experimental Study of Railway Ballast Consolidation Inhomogeneity under Vibration Loading
    (Akadémiai Kiadó, Hungary, 2020) Sysyn, Mykola P.; Kovalchuk, Vitalii V.; Gerber, Ulf; Nabochenko, Olga S.; Pentsak, Andriy Ya.
    EN: Railway ballast tamping is one of the cost-expensive renewal and maintenance works of railway superstructure. The quality of ballast consolidation influences its resistance to residual deformations and long-term deterioration of track geometry. The process of ballast compaction along the sleeper under the vibration loading is complex and depends on many factors. The ballast flow processes under the vibration loading can produce both consolidation and un-consolidation of ballast material. The present study is devoted to the experimental investigation of ballast consolidation inhomogeneity. The method of ballast local consolidation measurement is proposed. The method is based on the velocity of impact wave propagation that is measured with device. The application of modern microcontroller and sensor techniques provided simple and reliable multi-point velocity measurements in a ballast layer. That enables well enough spatial resolution of ballast consolidation inhomogeneity. The measurement analysis has shown more than 4 times higher consolidation under the sleeper center than for unconsolidated ballast.
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    Die Instandhaltung der Bettung
    (Železniční Dopravní Cesta 2011.VOŠ a SPŠ stavební, 2011) Sysyn, Mykola P.; Rybkin, Viktor V.; Nabochenko, Olga S.; Gerber, Ulf
    DE: Bei der Auslegung der Gleiskonstruktion oder der Festlegung der Betriebsbelastung wird bei der ukrainischen Eisenbahn die Leistungsfähigkeit der Schotterschicht durch einen Vergleich der berechneten und zulässigen Spannungen im Schotter bestimmt. Die zulässigen Spannungen werden nach der jährlichen Verkehrsbelastung und den Fahrzeugtypen unterschieden und erreichen Werte im Bereich von 0,15 bis 0,5 MPa (ЦП117) [1]. Derzeit wird jedoch immer offensichtlicher, dass die Übertragung des Kriteriums der zulässigen Spannungen auf den Schotter analog zu den anderen Bestandteilen des Oberbaus zu unakzeptablen Ergebnissen fuhrt. Der Hauptgrund hierfür ist die unscharfe Grenze zwischen einem arbeitsfähigen und nicht arbeitsfähigen Schotterzustand, welcher im Verlaufe der Lebensdauer einer ständigen Veränderung unterzogen ist. Ein weiterer Grund ist die fehlende Berücksichtigung der Instandhaltung auf die Lebensdauer der Schotterschicht. Darüber hinaus gibt es eine Reihe weiterer Faktoren, ohne deren Kenntnis die Beurteilung der Leistungsfähigkeit des Schotters schwierig ist. Das Ziel der vorliegenden Untersuchung besteht in der Optimierung der zulässigen vertikalen Gleislagefehler zur Minimierung der Stopfintervalle und damit der Minimierung der Schotterkosten überhaupt. Dabei wird Anfangsqualität des Fahrweges berücksichtigt. Diese wiederum ist vom Ungleichförmigkeitsgrad des Unterbaus und der Verdichtungsqualität der Bettungsschicht abhängig.
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    Modelling and Vehicle Based Measurements of Ballast Settlements Under the Common Crossing
    (Universita degli Studi di Trieste, Italy, 2019) Sysyn, Mykola P.; Gerber, Ulf; Grue, Dimitri; Nabochenko, Olga S.; Kovalchuk, Vitalii V.
    EN: Abstract. Railway turnout is geometrically and physically inhomogeneous object of railway superstructure. The common crossing zone is the high degradation processes are taking place in the common wingrail are wearing with inhomogen is uniformly deformed that lead to appearing the void wave along the crossing axis. The two deterioration processes are interconnected and both influence the dynamic loading. The paper deals with research of both influences based on the mathematical vehicle based measurements. The ballast settleme compared with the settlements measured with axle the base for the following inertial diagnostic vehicle and track based investigations as well as pl maintenance works at common crossing.
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    Prediction of Rail Contact Fatigue on Crossings Using Image Processing and Machine Learning Methods
    (Springer Verlag, Germany, 2019) Sysyn, Mykola P.; Gerber, Ulf; Nabochenko, Olga S.; Gruen, Dmitri; Kluge, Franziska
    EN: Abstract In this paper, an application of computer vision and machine learning algorithms for common crossing frog diagnostics is presented. The rolling surface fatigue of frogs along the crossing lifecycle is analysed. The research is based on information from high-resolution optical images of the frog rolling surface and images from magnetic particle inspection. Image processing methods are used to preprocess the images and to detect the feature set that corresponds to objects similar to surface cracks. Machine learning methods are used for the analysis of crack images from the beginning to the end of the crossing lifecycle. Statistically significant crack features and their combinations that depict the surface fatigue state are found. The research result consists of the early prediction of rail contact fatigue.
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    Stiffness and Strength of Structural Layers from Cohesionless Material
    (Versita, Great Britain, 2019) Gerber, Ulf; Sysyn, Mykola P.; Zarour, Jandab; Nabochenko, Olga S.
    EN: The deformation modulus and permissible stress are two independent parameters that depict the carrying capacity of foundations, including earthworks and ballast layer. Nevertheless, while designing the track superstructure or controlling its state, they are considered separate to each other, even though they are terms of the same measure. The scientific problem is due to the practical necessity of unified building rules and standards. The carrying capacity of earthworks and foundations is regulated with standards based both on deformation and on stress criteria, which are not related to each other. This plays particularly important role for railway ballast layer, as an intermediate between the solids and soil. The objective of the present research is to estimate the relationship between deformation modulus and the strength of ballast layer. An overview of modern approaches according to the relation between the stiffness, deformation modulus, elasticity and strength of soils and crushed stone is done. The strength of ballast layer is considered depending on the experimental test: the direct shear test, compressive strength in the uniaxial or biaxial stress state. Load transfer model in crushed stone is proposed. The load transfer angle and cone of loading distribution are determined based on the load transfer and compressive strength models. The relation between deformation modulus and strength is derived from two simple laboratory experiments with cohesionless ballast material. The experiment tests have shown that the ballast stiffness as well as its strength are influenced with the support stress. The measurement of elastic and residual settlements for the different support stress values enables to determine the relation. It can be potentially used for the development of methods for the ballast compaction control, unification of construction norms. The research result should be considered as an approach for unification of two different ways to reflect the carrying capacity of ballast layer.
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    Turnout Monitoring with Vehicle Based Inertial Measurements of Operational Trains: A Machine Learning Approach
    (University of Žilina, Slovakia, 2019) Sysyn, Mykola; Gruen, Dimitri; Gerber, Ulf; Nabochenko, Olga; Kovalchuk, Vitalii V.
    EN: A machine learning approach for the recent detection of crossing faults is presented in the paper. The basis for the research are the data of the axle box inertial measurements on operational trains with the system ESAH-F. Within the machine learning approach the signal processing methods, as well as data reduction classification methods, are used. The wavelet analysis is applied to detect the spectral features at measured signals. The simple filter approach and sequential feature selection is used to find the most significant features and train the classification model. The validation and error estimates are presented and its relation to the number of selected features is analysed, as well.
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    Turnout Remaining Useful Life Prognosis by Means of On-Board Inertial Measurements on Operational Trains
    (Taylor & Francis, 2020) Sysyn, Mykola P.; Gerber, Ulf; Kluge, Franziska; Nabochenko, Olga S.; Kovalchuk, Vitalii V.
    EN: The paper deals with remaining useful life (RUL) prognosis of common crossings based on inertial measurements. Axle-box inertial measurements on operational trains could be a cheap alternative to conventional inspection means. The low correlation between maximal wheel acceleration and useful life of the crossing is considered and the reasons are analysed. A machine learning approach, including feature extraction, selection, fusion and degradation modelling, is then used to cope with the problem. More time domain and spectral features are extracted from measured vertical accelerations to provide a higher utilization of the available information. After removing redundant features, the data is fused using principal component analysis to obtain a condition indicator for common crossings. A data-driven prognostic methodology is proposed based on an iteratively updated exponential degradation model. The assessment of the prognosis quality is carried out depending on the crossing lifetime and the reached value of the condition indicator.