Monte Carlo simulation of railway track geometry deterioration and restoration

2011 ◽  
Vol 226 (3) ◽  
pp. 274-282 ◽  
Author(s):  
L M Quiroga ◽  
E Schnieder
Keyword(s):  
High Speed ◽  
Railway Track ◽  
Ageing Process ◽  
Previous Knowledge ◽  
Planning And Scheduling ◽  
Track Geometry ◽  
Marquardt Algorithm ◽  
Non Linear ◽  
Maintenance Activities ◽  
Parameter Values

Travelling safely and comfortably on high-speed railway lines requires excellent conditions of the whole railway infrastructure in general and of the railway track geometry in particular. The maintenance process required to achieve such excellent conditions is complex and expensive, demanding a large amount of both human and technical resources. In this framework, choosing the right maintenance strategy becomes a critical issue. A reliable simulation of the railway geometry ageing process would offer a great advantage for the optimization of planning and scheduling of maintenance activities. A fundamental requirement for such simulation is a statistical model describing the behaviour of the railway track geometry deterioration as well as the effects of maintenance activities. The French railway operator SNCF has been periodically measuring the geometrical characteristics of its high-speed network since its commissioning (i.e. for more than 20 years now). These records are an excellent data source to achieve a sound statistical description of the process. In this paper a new system identification method to obtain such simulations is presented. The proposed method uses a grey-box model: a model structure and its constraints are specified basing on previous knowledge of the process to be identified, and then the set of parameter values which best fits the signal measurements is searched. As previous knowledge indicates that the process is non-linear, parameter values are searched by means of the Levenberg–Marquardt algorithm, an iterative technique that finds a local minimum of a function that is expressed as the sum of squares of non-linear functions. Furthermore, the presented model is extended in order to analyse the effect of the variation of factors influencing the ageing process (e.g. operational speed). Finally, the method is applied and validated with real data of a French high-speed TGV line.

Wu Guang High-Speed Rail Track Irregularity Power Spectrum Analysis

2014 ◽  
Vol 638-640 ◽  
pp. 1224-1228 ◽  
Author(s):  
Ji Yang Li ◽  
Lin Ya Liu ◽  
Dong Hua Kou
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Railway Track ◽  
High Speed Rail ◽  
Track Geometry ◽  
Railway Line ◽  
Spectrum Density ◽  
Track Irregularity ◽  
Parameter Values ◽  
Geometry Inspection

Irregularity is the locomotive and the main excitation source of vibration, is directly related to the smooth running of the train, safety and comfort, is to control the maximum operating speed of the train one of the main factors. The statistic specimen was collected by track geometry inspection car from Wuhan-Guangzhou high-speed rail. Based on the stationarity test of the specimen, Fast Fourier Transform (FFT) method was used to evaluate the spectrum of the whole specimen space. The power spectrum density (PSD) and related functions of track irregularity were obtained by MATLAB program. We analyzed it by comparing the fitting curve of the national speed lines and fitting curve of Qinhuangdao-Shenyang dedicated passenger railway line, by comparison, the Wuhan-Guangzhou high-speed railway track irregularity is much better than the national speed lines and Qinhuangdao-Shenyang dedicated passenger railway line. The parameter values of PSD fitting curve for track irregularity are obtained by the nonlinear curve-fitting algorithm in the least-squares sense, which has referencing value to maintenance high-speed rail.

scholarly journals The Design and Implementation of an Inertial GNSS Odometer Integrated Navigation System Based on a Federated Kalman Filter for High-Speed Railway Track Inspection

2021 ◽  
Vol 11 (11) ◽  
pp. 5244
Author(s):  
Xinchun Zhang ◽  
Ximin Cui ◽  
Bo Huang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
High Speed ◽  
Measurement Accuracy ◽  
Railway Track ◽  
Filter Method ◽  
Integrated Navigation ◽  
High Speed Railway ◽  
Track Geometry ◽  
Integrated Navigation System

The detection of track geometry parameters is essential for the safety of high-speed railway operation. To improve the accuracy and efficiency of the state detector of track geometry parameters, in this study we propose an inertial GNSS odometer integrated navigation system based on the federated Kalman, and a corresponding inertial track measurement system was also developed. This paper systematically introduces the construction process for the Kalman filter and data smoothing algorithm based on forward filtering and reverse smoothing. The engineering results show that the measurement accuracy of the track geometry parameters was better than 0.2 mm, and the detection speed was about 3 km/h. Thus, compared with the traditional Kalman filter method, the proposed design improved the measurement accuracy and met the requirements for the detection of geometric parameters of high-speed railway tracks.

Influence of Construction of Railway Superstructure on Railway Quality

2014 ◽  
Vol 617 ◽  
pp. 54-59
Author(s):  
Libor Ižvolt ◽  
Jana Ižvoltová ◽  
Janka Šestáková
Keyword(s):  
High Speed ◽  
Railway Track ◽  
Track Geometry ◽  
Railway Tracks ◽  
Rail Vehicles ◽  
Operational Load ◽  
Safety And Reliability ◽  
Maintenance Work ◽  
The Cost

The operation of railway tracks is historically confirmed that the classic structure of the railway superstructure is capable to ensure operational capability of standard railway tracks for a relatively long period of time (railways tracks to speed of 160 km.h-1). Such a railway track and its track is considered the railway track with a classic structure of the railway superstructure, where track removal is stored in the ballast. In the case of high operating and axle load, increasing track speed and requirements for safety of operation, which are associated with high requirements on the track geometry, it appears that such structure has its operational (in terms of guaranteeing the long-term safety and reliability of the railway track) and economic (in terms of the cost of maintenance of railway track) limits. "Floating" placement of the track removal during each passage of a rail vehicle, or train leads to the growth of dynamic horizontal and vertical forces that cause gradual degradation of track geometry, what subsequently leads to restless journey of moving rail vehicles. Elimination of imperfections in track geometry - the quality of the railway track - forces the operators to remove such imperfections of railway track in time and financially consuming maintenance work in certain periods. However, it is sufficient if only the weakest element of classic railway superstructure is replaced in the railway, and it is the track ballast using other more appropriate component representing no elastic and plastic behaviour. The structure is such replacement, in which the track removal is concreted (monolithic structure) or stored on a concrete or asphalt bearing layer (layered structure), namely structural design, which is referred to as unconventional railway superstructure. The structure of railway superstructure is characterized by cross sleepers used in a modified shape or they are not part of it at all. Currently, thus conceived railway track is referred to as a slab track (hereinafter referred to as the "ST"), which requires flexibility of the railway superstructure for the system of the wheel/rail secured using elastic elements disposed between the rail and the sleeper and/or under the sleeper. In general, the structure of ST has been currently applied mainly to high-speed track and the tracks that have high operational load, where the cost of maintaining the track with the classic structure of the railway superstructure strongly grows. At the same time, however, this structure also promotes in the upgraded sections of the standard tracks (track speed to 160 km.h-1), especially in track sections conducted in tunnels, as there are located the required properties of the ballast that do not demonstrate subsidence. The subgrade without a drop also offers for application of the ST structure bridges, and therefore, the application of this structure is also possible in these track sections.

Calculation model of the vehicle – CRTS II coupling system with symplectic method

2017 ◽  
Vol 232 (4) ◽  
pp. 959-969 ◽  
Author(s):  
Ping Wang ◽  
Jinhui Xu ◽  
Li Wang ◽  
Kai Wei
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Structural Characteristics ◽  
Calculation Model ◽  
Railway Track ◽  
Symplectic Method ◽  
Track Geometry ◽  
Vertical Coupling ◽  
Ballastless Track ◽  
Coupling System

In this paper, the vibrations of the vehicle – CRTS II (abbreviation for China Railway Track System II) slab ballastless track vertical coupling system for high-speed railways were studied. Based on the structural characteristics of the CRTS II ballastless track, a dynamic model of the CRTS II ballastless track was established, and an effective calculation method was applied to determine the frequency response of the system. In this method, the track structure was divided into innumerable substructures by fastener spacing. Four substructures under the wheel–rail force were chosen as the subject while the transmission of simple harmonic waves in such track substructures were solved using the symplectic method. In addition, the transfer function between the track irregularities and the dynamic response of the coupling system was solved, and with these results, the coupling system’s frequency response was obtained. Furthermore, the method was proven accurate and efficient (see examples in this paper). The effects of track parameters on the coupling system’s frequency response were also studied, which provide a basis for the optimization of the design of the CRTS II ballastless track. As shown in the study, with respect to the desired track geometry and dynamic displacement, the application of the fastening system featuring low stiffness and large damping can effectively reduce the frequency response of the coupling system, while the elastic modulus and damping of the cement asphalt mortar exert the least impact on the frequency response. In addition, the subgrade stiffness shall be managed at an appropriate level, and greater subgrade damping can effectively minimize the coupling system’s vibrations.

scholarly journals The impact of summer heatwaves on railway track geometry maintenance

2021 ◽  
pp. 095440972098429
Author(s):  
Ben Davies ◽  
John Andrews
Keyword(s):  
Asset Management ◽  
Response Times ◽  
Railway Track ◽  
Management Support ◽  
Maintenance Policy ◽  
Management Tools ◽  
Support Tool ◽  
Track Geometry ◽  
Maintenance Activities ◽  
The Impact

Elevated summer temperatures are a disrupting factor on the rail network. Due to the risk of a track buckling under thermal expansion forces, geometry maintenance must be delayed during heatwaves, leading to an overall decreased network availability and reliability. Track asset management support tools are used to plan and schedule a variety of maintenance activities, with tamping and stoneblowing being the primary activities for geometry maintenance. No management tools seen in the literature consider the influences of weather on the scheduling and delivery of maintenance. This paper describes a Petri net modelling approach to railway track asset management. This is demonstrated to be a highly flexible method able to capture the complexities of degradation, inspection, and maintenance, and predict the evolution of track geometry quality over time. Different maintenance strategies are tested, varying the degradation thresholds, inspection intervals, policy decisions, and maintenance response times. Excessively hot weather is introduced as an inhibiting factor for all maintenance activities, resulting in extended periods where interventions are delayed. Simulation results show that frequent inspection and timely maintenance scheduling strategies could be followed to attain a highly performing and resilient track system. This asset management support tool could be added to the suite used by the rail industry, providing guidance on maintenance policy through a summer season where heatwave disruptions are expected.

scholarly journals Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5446 ◽  
Author(s):  
Zai-Wei Li ◽  
Xiao-Zhou Liu ◽  
Yue-Lei He
Keyword(s):  
High Speed ◽  
Detection Method ◽  
Measurement Data ◽  
Railway Track ◽  
Discrete Wavelet ◽  
High Speed Rail ◽  
Track Geometry ◽  
Slab Track ◽  
Geometry Measurement ◽  
Inspection Data

Slab track is widely used in many newly built high-speed rail (HSR) lines as it offers many advantages over ballasted tracks. However, in actual operation, slab tracks are subjected to operational and environmental factors, and structural damages are frequently reported. One of the most critical problems is temperature-induced slab-warping deformation (SWD) which can jeopardize the safety of train operation. This paper proposes an automatic slab deformation detection method in light of the track geometry measurement data, which are collected by high-speed track geometry car (HSTGC). The characteristic of track vertical irregularity is first analyzed in both time and frequency domain, and the feature of slab-warping phenomenon is observed. To quantify the severity of SWD, a slab-warping index (SWI) is established based on warping-sensitive feature extraction using discrete wavelet transform (DWT). The performance of the proposed algorithm is verified against visual inspection recorded on four sections of China HSR line, which are constructed with the China Railway Track System II (CRTSII) slab track. The results show that among the 24,806 slabs being assessed, over 94% of the slabs with warping deformation can be successfully identified by the proposed detection method. This study is expected to provide guidance for efficiently detecting and locating slab track defects, taking advantage of the massive track inspection data.

scholarly journals Delayed maintenance modelling considering speed restriction for a railway section

2017 ◽  
Vol 231 (4) ◽  
pp. 411-428
Author(s):  
Hui Shang ◽  
Christophe Bérenguer ◽  
John Andrews
Keyword(s):  
Survival Time ◽  
Preventive Maintenance ◽  
Railway Track ◽  
System Throughput ◽  
Maintenance Cost ◽  
Decision Variable ◽  
Track Geometry ◽  
Coloured Petri Net ◽  
Maintenance Activities ◽  
System Benefit

The deterioration of track geometry depends on several factors of which the speed of the train is one. Imposing a speed restriction can slow down the track deterioration and allows a longer survival time before a serious condition is achieved. Preventive maintenance delays can be authorized during the survival time. However, speed restrictions also reduce the system throughput. On the other hand, a longer interval between preventive maintenance activities has a lower maintenance action cost and it also enables grouping the maintenance activities to save set-up costs as well as system downtime. If the repair delay is too long, it may cause unacceptable conditions on the track and lead to higher maintenance costs and accidents. Therefore, it is interesting to assess the effect of a speed restriction on the delayed maintenance strategies for a railway track section. We want to solve a maintenance optimization problem to find the optimal tuning of the maintenance delay time and imposition of a speed restriction. To this aim, a delayed maintenance model is developed, in which track deterioration depends on the train speed and the number of passing trains. The model is used to determine an optimal speed restriction strategy and a preventive repair delay for the optimization of the system benefit and unavailability. Coloured Petri Nets are adopted to model the maintenance and operation of the railway track section. The Coloured Petri Net model describes the gradual track deterioration as a stochastic process. Different speed restriction policies and maintenance delay strategies are modelled and activated by the observed component states. Monte Carlo simulations are carried out to estimate the maintenance cost, the system benefit and the system downtime under different policies. Numerical results show the maintenance decision variable trade-off.

scholarly journals An efficient physical-based method for predicting the long-term evolution of vertical railway track geometries

2021 ◽  
pp. 095440972110248
Author(s):  
Nishant Kumar ◽  
Claudia Kossmann ◽  
Stephan Scheriau ◽  
Klaus Six
Keyword(s):  
Long Term Evolution ◽  
Contact Forces ◽  
Railway Track ◽  
Model Parameters ◽  
Relative Height ◽  
Vehicle Model ◽  
Track Geometry ◽  
Term Evolution ◽  
Maintenance Activities

The dynamic wheel-rail contact forces resulting from the interaction between vehicle and track are responsible for the local track settlement. If these local settlements vary along the track, geometric irregularities develop further amplifying the dynamic loading of the track caused by the interaction between the vehicle and track. In this work, an efficient vehicle-track interaction (VTI) model is presented for predicting the long-term evolution of vertical track settlement during operation. The VTI model has two interacting components – vehicle and track. The vehicle model describes the vertical dynamics of an 8th of a car. The track model considers an elastic rail on discrete (sleeper) supports. Each sleeper location can have its own stiffness, relative height and settlement characteristics. Dependent on the distribution of stiffness and settlement behaviour along the track together with the initial track geometry, each sleeper settles dependent on the number of load cycles (vehicle passes). The track model is initialized with measured vertical track geometry data and static track deflection data at the beginning (day 0) for two types of track sections in the field, a track section where concrete sleepers with Under Sleeper Pads (USP) are used and a track section where only concrete sleepers are used. Using the same settlement model parameters (constant along the track) for the two tracks, the physical-based VTI model can predict the different track geometry quality evolution for both tracks over 350 days. Finally, the VTI model is used to assess the track geometry deterioration when the track/vehicle properties are changed. The prediction strength of the fast VTI model based on the physical understanding can assist in designing and optimizing tracks and in supporting of maintenance activities.

scholarly journals A Taxonomy of Railway Track Maintenance Planning and Scheduling: A Review and Research Trends

2021 ◽  
pp. 107827
Author(s):  
Mahdieh Sedghi ◽  
Osmo Kauppila ◽  
Bjarne Bergquist ◽  
Erik Vanhatalo ◽  
Murat Kulahci
Keyword(s):  
Research Trends ◽  
Railway Track ◽  
Maintenance Planning ◽  
Planning And Scheduling ◽  
Track Maintenance

scholarly journals Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3609
Author(s):  
Mykola Sysyn ◽  
Michal Przybylowicz ◽  
Olga Nabochenko ◽  
Lei Kou
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Dynamic Interaction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Monitoring Methods ◽  
Beam Dynamic ◽  
Track Geometry ◽  
Data Driven Approach ◽  
Support Conditions

The ballasted track superstructure is characterized by a relative quick deterioration of track geometry due to ballast settlements and the accumulation of sleeper voids. The track zones with the sleeper voids differ from the geometrical irregularities with increased dynamic loading, high vibration, and unfavorable ballast-bed and sleeper contact conditions. This causes the accelerated growth of the inhomogeneous settlements, resulting in maintenance-expensive local instabilities that influence transportation reliability and availability. The recent identification and evaluation of the sleeper support conditions using track-side and on-board monitoring methods can help planning prevention activities to avoid or delay the development of local instabilities such as ballast breakdown, white spots, subgrade defects, etc. The paper presents theoretical and experimental studies that are directed at the development of the methods for sleeper support identification. The distinctive features of the dynamic behavior in the void zone compared to the equivalent geometrical irregularity are identified by numeric simulation using a three-beam dynamic model, taking into account superstructure and rolling stock dynamic interaction. The spectral features in time domain in scalograms and scattergrams are analyzed. Additionally, the theoretical research enabled to determine the similarities and differences of the dynamic interaction from the viewpoint of track-side and on-board measurements. The method of experimental investigation is presented by multipoint track-side measurements of rail-dynamic displacements using high-speed video records and digital imaging correlation (DIC) methods. The method is used to collect the statistical information from different-extent voided zones and the corresponding reference zones without voids. The applied machine learning methods enable the exact recent void identification using the wavelet scattering feature extraction from track-side measurements. A case study of the method application for an on-board measurement shows the moderate results of the recent void identification as well as the potential ways of its improvement.

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