Research of lateral vibrations of a passenger wagon running along the curved path

The objective of this work is to study transverse vibration of a passenger car body running at various speeds over the track irregularities, which are usually encountered in practice. The tasks that are addressed in this research work: perform tests at track irregularities of symmetrical sinusoidal shape running both along straight and curved paths, as well as driving over the junctions along the straight and curved paths, and compare the results

On-line monitoring of vertical long wavelength track irregularities using bogie pitch rate

Long wavelength track irregularities are the key factors which influence vehicle stability and comfort. An on-line monitoring method is proposed to detect the vertical long wavelength track irregularities based on bogie pitch rate. Firstly, the principle of on-line monitoring method based on axle-box acceleration or bogie pitch rate was presented. Secondly, to process bogie pitch rate, a mix-filtering approach which contains time-space domain transformation, double integration, baseline correction and RLS (Recursive Least Squares) adaptive compensation filter was proposed. Thirdly, a coupling dynamics model of vertical vehicle-track interactions was developed to obtain bogie pitch rate. The obtained bogie pitch rate was then filtered with the signal processing approach. When the processed result compares with the actual irregularities, the SD (Standard Deviation) is 0.327 mm and the NMSE (Normalized Mean Square Error) is –9.1495. The experimental result shows that the proposed on-line monitoring method based on bogie pitch rate and signal processing approach are capable of monitoring the long wavelength track irregularities accurately and effectively

Feasibility of Applying Mel-Frequency Cepstral Coefficients in a Drive-by Damage Detection Methodology for High-Speed Railway Bridges

In this paper, a drive-by damage detection methodology for high-speed railway (HSR) bridges is addressed, to appraise the application of Mel-frequency cepstral coefficients (MFCC) to extract the Damage Index (DI). A finite element (FEM) 2D VTBI model that incorporates the train, ballasted track and bridge behavior is presented. The formulation includes track irregularities and a damaged condition induced in a specified structure region. The feasibility of applying cepstrum analysis components to the indirect damage detection in HSR by on-board sensors is evaluated by numerical simulations, in which dynamic analyses are performed through a code implemented in MATLAB. Different damage scenarios are simulated, as well as external excitations such as measurement noises and different levels of track irregularities. The results show that MFCC-based DI are highly sensitive regarding damage detection, and robust to the noise. Bridge stiffness can be recognized satisfactorily at high speeds and under different levels of track irregularities. Moreover, the magnitude of DI extracted from MFCC is related to the relative severity of the damage. The results presented in this study should be seen as a first attempt to link cepstrum-based features in an HSR drive-by damage detection approach.info:eu-repo/semantics/publishedVersio

NUMERICAL SYNTHESIS OF THE TRACK ALIGNMENT AND APPLICATIONS. PART II: THE SIMULATION OF THE DYNAMIC BEHAVIOUR IN THE RAILWAY VEHICLES

Summary. This paper features a method of synthesizing the track irregularities by which the alignment may be analytically represented by a pseudo-stochastic function, as well as the implementation of such a method in the numerical simulation of the dynamic behaviour of the railway vehicles. The method described in Part I relies on the power spectral density of the track irregularities, as per ORE B 176 and the specifications included in UIC 518 Leaflet regarding the track's geometric quality. Part II shows the results of the numerical simulations regarding the lateral behaviour of the railway vehicle during the circulation on a tangent track with lateral irregularities, synthesized as in the method herein. These results point out many basic properties of the lateral vibration behaviour of the railway vehicle, a fact that demonstrates the efficiency of the suggested method

Improved Railway Track Irregularities Classification by a Model Inversion Approach

Over time railway networks have become complex Systems characterized by manifold types of technical components with a broad range of age distribution. De facto, about 50 percent of the life cycle costs of railway infrastructures are made up by direct and indirect maintenance costs. A remedy can be provided by a condition based preventive maintenance strategy leading to an optimized scheduling of maintenance actions taking the actual aswell as the expected future infrastructure condition into account. A prerequisite is, however, that the thousands of Kilometers of railway tracks are almost continuously monitored. Thus, a promising approach is the usage of low-cost sensors, e.g. accelerometers and gyroscopes, which can be installed on common in-line freight and passenger trains. Due to ambiguous data records a credible classification of railway track irregularities directly from these data is challenging. Alternatively to this pure data-driven approach, in this paper a novel hybrid Approach is presented. To this end, a simplified vehicle Suspension model is applied for the purpose of railway track condition monitoring by analyzing the dynamic railway track - Train interactions. The inversion of the model can be used to recalculate the actual inputs (irregularities) of the monitored system (rail surface) which have caused recorded System Responses (dynamic vehicle reactions and acceleration data, respectively). These recalculated inputs are a sound Basis of subsequent data-driven condition monitoring analyses. In this preliminary study, a classification algorithm is implemented to identify a simulated railway track irregularity automatically

Dynamic Response of Commuter Rail Vehicle under Lateral Track Irregularity

Lateral track irregularities normally occur when both rail lines have some displacement laterally with respect to the original track due to prolonged exposure to sun’s heat, or may also arise from specific features such as switch and crossing work of track. These track irregularities will cause unwanted body vibration of commuter rail vehicle. These vibrations have to be suppressed for the purpose of ride comfort. This paper presents two control strategies in semi-active suspension systems which are PID and disturbance rejection control to improve passenger ride comfort. A half car model of commuter rail vehicle with three-degree-of-freedom (3-DOF) was developed based on Newton's Second Law. Vibration analyses based on simulation results in time domains are compared with passive system using MATLAB-Simulink software. The results show that the semi-active controllers are able to suppress rail vehicle body responses effectively

Analysis of Railway Track Irregularities with Convolutional Autoencoders and Clustering Algorithms

Modern maintenance strategies for railway tracks rely more and more on data acquired with low-cost sensors installed on in-service trains. This quasi-continuous condition monitoring produces huge amounts of data, which require appropriate processing strategies. Deep learning has become a promising tool in analyzing large volumes of sensory data. In this work, we demonstrate the potential of artificial intelligence to analyze railway track defects. We combine traditional signal processing methods with deep convolutional autoencoders and clustering algorithms to find anomalies and their patterns. The methods are applied to real world data gathered with a multi-sensor prototype measurement system on a shunter locomotive operating on the industrial railway network of the inland harbor of Braunschweig (Germany). This work shows that deep learning methods can be applied to find patterns in railway track irregularities and opens a wide area of further improvements and developments

Analysis of Lateral Displacements in Large Railway Viaducts Under Traffic Loads. Impact on Ride Safety and Passenger Comfort.

The increasing design speed of the new high speed lines and the stringent requirements on track alignment parameters are leading to a sustained increase of the number of railway viaducts. The relevant standards impose limiting values on lateral vibrations. Both the Spanish and European standards establish a minimum value for the first natural frequency of lateral vibration of a span, that should not be lower than fh0 = 1,2 Hz. This limit was originally proposed by ERRI committee D181, which assessed the lateral forces in railway bridges. This limit was proposed in order to avoid lateral resonance in railway vehicles going across the structure, taking into account that the frequencies of lateral vibration of railway vehicles are, in general, not greater than 1,0 Hz. In the case of large continuous viaducts with high piers, the lateral deformations occurring during a train pass-by can be significant and the natural frequencies of the first mode of vibration of the deck can be very low. In these cases it is not clear whether the required verifications must be applied to spans considered independently, to several successive spans or to the whole viaduct. There is currently no analysis methodology allowing to assess this situation and check the viaduct design against the requirements of ride safety and passenger comfort. This paper analyzes the lateral deformations of a large continuous viaduct and the infrastructure vehicle interaction effects due to the circulation of freight trains and several types of high speed train sat different speeds. The application of this methodology will allow an optimized design of viaducts with significant lateral deformations that cannot be justified only by using the simplified criteria of the current applicable standards. In such cases, the compliance with standards may lead to over dimensioning or in other cases to neglect the limits without the adequate verification of the proper infrastructure behavior once it has been commissioned. As it is the case for vertical deformations, for which the European standards require the assessment of dynamic effects, we stress the need for a dynamic analysis of the effects of lateral deformations in large railway viaducts