scholarly journals Measurement of Railway Track Geometry: A State-of-the-Art Review

2019 ◽  
Vol 48 (1) ◽  
pp. 76-88
Author(s):  
András Farkas
Keyword(s):  
Contact Forces ◽  
Railway Track ◽  
Motion Sensors ◽  
Position Information ◽  
Track Geometry ◽  
Measurement Systems ◽  
Track System ◽  
Railway Engineering ◽  
Rail Inspection

The worldwide increase in frequency of traffic for passenger trains and the rise of freight trains over the recent years necessitate the more intense deployment of track monitoring and rail inspection procedures. The wheel-rail contact forces, induced by the static axle loads of the vehicle and the dynamic effects of ground-borne vibration coming from the track superstructure, have been a significant factor contributing to the degradation of the railway track system. Measurements of track irregularities have been applied since the early days of railway engineering to reveal the current condition and quality of railway lines. Track geometry is a term used to collectively refer to the measurable parameters including the faults of railway tracks and rails. This paper is aiming to review the characteristics of compact inertial measurement systems (IMUs), their components, installation, the basic measures of the quality of the track using motion sensors, like accelerometers, gyroscopes and other sensing devices mounted on different places of the vehicle. Additionally, the paper briefly discusses the fundamentals of inertial navigation, the kinematics of the translational and rotational train motions to obtain orientation, velocity and position information.

scholarly journals Preliminary study of shaping the railway track geometry in terms of their maintenance costs and capacity

2020 ◽  
Vol 53 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Piotr Gołębiowski ◽  
Jacek Kukulski
Keyword(s):  
Asset Management ◽  
Transport Infrastructure ◽  
Railway Track ◽  
Risk Level ◽  
Maintenance Costs ◽  
Track Geometry ◽  
Track System ◽  
System Solution ◽  
New Construction ◽  
Infrastructure Maintenance

In Poland, due to the increase in investments made by railways in recent years, and thus the increase in the replacement value of transport infrastructure, the need for expenditure on infrastructure maintenance will increase in the next 30 years, or the development of the developed transport network will degrade. As part of the overall discipline of resource management, subdiscipline has emerged - infrastructure asset management. As part of the management of railway transport infrastructure, the demand for cheaper maintenance costs will grow. The cost reduction of infrastructure maintenance is possible through meticulous assessment of its condition, rational selection of locations and scope of repairs at the assumed risk level, as well as at the stage of preparation of new construction or modernization projects taking into account aspects of later maintenance. For some time, we have been observing the accumulation of knowledge (methods, programs, procedures) in the country and abroad enabling optimization of infrastructure condition assessment and programming of its maintenance. The implementation of these solutions may result in a more rational use of funds for infrastructure maintenance and not disturb its smooth functioning in operation. The article discusses aspects that should be considered in the design process of railway infrastructure. Particular attention was paid to the durability of steel components of the railway superstructure, maintenance costs as well as aspects related to the capacity of the track node. An example of dependence of selected values of radial arcs depending on their durability and maintenance costs was presented. It was proposed to change the track layout at the Warszawa Srodmiescie passenger stop planned for reconstruction. Calculations of kinematic parameters for various configurations of railway turnouts were performed. Also, calculations of the capacity for the existing track system solution as well as the proposed track system after reconstruction of the analysed Warszawa Srodmiescie railway station were also carried out.

Coupling OCREC Contact Code With ADAMS: Simulations of One Coach at 130mph

2009 ◽  
Author(s):  
J. P. Pascal ◽  
J. Berger ◽  
F. Bondon ◽  
C. Clerc ◽  
S. Teppe
Keyword(s):  
High Speed ◽  
Model Updating ◽  
Contact Forces ◽  
Railway Track ◽  
Frenet Frame ◽  
Time Step ◽  
Space Curves ◽  
Track System ◽  
Curvature Measurements ◽  
Multi Body

This paper presents the Online Calculation of Railway Elastic Contacts (OCREC), a dynamic railway calculation tool based on an advanced contact kernel, and its coupling with the MSC ADAMS multi-body commercial software. The OCREC contact kernel is used as a subroutine of multi-body codes in order to calculate contact forces between wheelsets and rails. The OCREC method is “online” as it not only redefines new contact parameters at each time step but also determines all simultaneous contacts on each wheel as allowed by Hertz Elasticity theory. From the normal forces and relative velocities given by the Hertz theory, Tangential Forces are calculated using Kalker’s FASTSIM (modified for elliptical pressure distribution). After a description of the OCREC theory, the paper presents the linkage between OCREC and MSC ADAMS software. OCREC calculates contact forces within a Frenet frame (oxyz) following the track layout where ox is tangent to the track; oy is horizontal and oz normal to oxy. As ADAMS calculates inside a different frame, and as it has no built-in track system, it was necessary to develop a program capable of connecting 3 different frames: the ‘dummy’ track frame, the Frenet frame and the fixed ADAMS frame. Note that the ‘dummy’ frame is directly calculated from railway track curvature measurements recorded in so-called ‘space curves’. The OCREC ADAMS link is first validated by a bogie rolling on a dummy track. With the equations of the OCRECYM code established directly within the “dummy” frame, the OCREC-ADAMS results are compared to a specific OCRECYM validation code. Then, the results from an actual railway case are presented: behavior of one coach is calculated on a real measured track including curves and defaults. During the following step, the OCREC-ADAMS results are compared to OCRECYM results. After some model updating for adjustment to physical properties of elastic joints (helicoidal springs), a good correlation is obtained between the codes. The analysis of the different force and displacement components proves this kind of numerical tool’s capabilities of assessing the railway vehicle’s dynamic behavior. Especially, the Y/Q safety ratio is well calculated. Thus, the OCREC contact kernel, which is powerful for complex contact topologies such as conformal contacts, and necessary for high speed safety calculation, can be used as a subroutine of standard multi-body software, giving it high capabilities for dynamic railway calculation.

scholarly journals GELEŽINKELIO KELIO GEOMETRINIŲ PARAMETRŲ DINAMIKOS TYRIMAS TAIKANT KELIO KOKYBĖS INDEKSĄ / RAILWAYS GEOMETRICAL PARAMETERS DYNAMICS INVESTIGATION BY TRACK QUALITY INDEX

2018 ◽  
Vol 10 (0) ◽  
pp. 1-7
Author(s):  
Vytautas Motiejus Bubnelis ◽  
Benas Slepakovas ◽  
Laura Černiauskaitė ◽  
Henrikas Sivilevičius
Keyword(s):  
Quality Index ◽  
Rail Transport ◽  
Geometric Parameters ◽  
Railway Track ◽  
Geometrical Parameters ◽  
Track Geometry ◽  
Track Condition ◽  
Over Time ◽  
Track Quality

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.

scholarly journals Performance of railway track system under harmonic loading by finite element method

2018 ◽  
Vol 162 ◽  
pp. 01043
Author(s):  
Ammar Shuber ◽  
Mohammed Hamood ◽  
Walaa Jawad
Keyword(s):  
Soil Structure ◽  
Theoretical Models ◽  
Contact Forces ◽  
Railway Track ◽  
Ansys Software ◽  
Applied Loading ◽  
High Speeds ◽  
Track System ◽  
European Code ◽  
Real Behavior

The performance of railway track under dynamic loading depends on many parameters such as type of sleepers, ballast, soil - structure interaction and the relation of contact forces between the track and railway. The rail track classified as low and high speeds, where speed is a very important factor in design. Many theoretical models were derived and some developed for dynamic analysis of railway track system with assumptions that simplified or matched actually the real behavior especially the support of sleepers as linear or nonlinear and the contact between railway and track. In the present paper, a Finite Elements Approach is one of the numerical analysis by ANSYS software that adopted here to study the performance of harmonic analysis of railway track system. Harmonic ranges were applied with constant applied loading based on the European code for the steel rail.

scholarly journals Effects of Differential Subgrade Settlement on Slab Track Deformation Based on a DEM-FDM Coupled Approach

2021 ◽  
Vol 11 (4) ◽  
pp. 1384
Author(s):  
Xuhao Cui ◽  
Rui Zhou ◽  
Gaoran Guo ◽  
Bowen Du ◽  
Hanlin Liu
Keyword(s):  
Contact Force ◽  
Three Dimensional ◽  
Coupled Model ◽  
Contact Forces ◽  
Railway Track ◽  
Slab Track ◽  
Maximum Value ◽  
Track System ◽  
Track Deformation ◽  
Maximum Contact

Slab track structures become deformed under the effects of differential subgrade settlement. According to the properties of the China Railway Track System (CRTS) II slab track on a subgrade, a three-dimensional (3D) coupled model based on both the discrete element method (DEM) and finite difference method (FDM) was developed. The slab track and subgrade were simulated using the FDM and DEM, respectively. The coupled model was verified. The deformation of the slab track and contact forces of gravel grains in the surface layer of the subgrade were studied under differential subgrade settlement. The effects of settlement wavelength, settlement amplitude, and other types of settlements were also discussed. The results demonstrate that the settlement amplitude and settlement wavelength of the subgrade have significant effects on track deformation. The deformation amplitude of the slab track increases nonlinearly with an increasing settlement amplitude of the subgrade. Increases in the settlement wavelength and amplitude of the subgrade significantly increase the maximum value of the contact force of the gravel grains in the subgrade. The maximum contact force of gravel grains near the boundaries of the settlement section can reach two to three times that of the unsettled condition, which makes it easy to accelerate the plastic settlement of the subgrade.

scholarly journals Extracting Rail Track Geometry from Static Terrestrial Laser Scans for Monitoring Purposes

2014 ◽  
Vol XL-5 ◽  
pp. 553-557 ◽  
Author(s):  
A. Soni ◽  
S Robson ◽  
B Gleeson
Keyword(s):  
Point Cloud ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Railway Track ◽  
Monitoring Tool ◽  
Track Geometry ◽  
Rail Track ◽  
Target Locations ◽  
Track Monitoring

This paper presents the capabilities of detecting relevant geometry of railway track for monitoring purposes from static terrestrial laser scanning (TLS) systems at platform level. The quality of the scans from a phased based scanner (Scanner A) and a hybrid timeof- flight scanner (Scanner B) are compared by fitting different sections of the track profile to its matching standardised rail model. The various sections of track investigated are able to fit to the model with an RMS of less than 3 mm. Both scanners show that once obvious noise and artefacts have been removed from the data, the most confident fit of the point cloud to the model is the section closest to the scanner position. The results of the fit highlight the potential to use this method as a bespoke track monitoring tool during major redevelopment projects where traditional methods, such as robotic total stations, results in missed information, for example due to passing trains or knocked prisms and must account for offset target locations to compute track parameters.

Accurate Representation of the Rail Geometry for Multibody System Applications

2009 ◽  
Vol 5 (1) ◽  
Author(s):  
Brian Marquis ◽  
Khaled E. Zaazaa ◽  
Tariq Sinokrot ◽  
Ahmed A. Shabana
Keyword(s):  
Space Curve ◽  
Contact Forces ◽  
Railway Track ◽  
Bank Angle ◽  
Space Curves ◽  
The Right ◽  
Yaw Angle ◽  
Horizontal Curvature ◽  
The Relationship

The objective of this study is to examine the geometric description of the spiral sections of railway track systems, in order to correctly define the relationship between the geometry of the right and left rails. The geometry of the space curves that define the rails are expressed in terms of the geometry of the space curve that defines the track center curve. Industry inputs such as the horizontal curvature, grade, and superelevation are used to define the track centerline space curve in terms of Euler angles. The analysis presented in this study shows that, in the general case of a spiral, the profile frames of the right and left rails that have zero yaw angles with respect to the track frame have different orientations. As a consequence, the longitudinal tangential creep forces acting on the right and left wheels, in the case of zero yaw angle, are not in the same direction. Nonetheless, the orientation difference between the profile frames of the right and left rails can be defined in terms of a single pitch angle. In the case of small bank angle that defines the superelevation of the track, one can show that this angle directly contributes to the track elevation. The results obtained in this study also show that the right and left rail longitudinal tangents can be parallel only in the case of a constant horizontal curvature. Since the spiral is used to connect track segments with different curvatures, the horizontal curvature cannot be assumed constant, and as a consequence, the right and left rail longitudinal tangents cannot be considered parallel in the spiral region. Numerical examples that demonstrate the effect of the errors that result from the assumption that the right and left rails in the spiral sections have the same geometry are presented. The numerical results obtained show that these errors can have a significant effect on the quality of the predicted creep contact forces.

Rail vehicle model motion analysis on curved track with vertical irregularity

2020 ◽  
Vol 130 ◽  
pp. 75-84
Author(s):  
Mirosław Dusza
Keyword(s):  
Contact Forces ◽  
Railway Track ◽  
Temperature Changes ◽  
Track System ◽  
Standards And Regulations ◽  
Vehicle Motion ◽  
Track Irregularity ◽  
Atmospheric Phenomena ◽  
The Impact ◽  
Track Deformation

The properties of a classic railway track largely depend on the properties of the sub-grade, which is most often a natural creation. Atmospheric phenomena (e.g. temperature changes, heavy rainfall) can locally reduce the elasticity of the subgrade and create conditions conducive to permanent track deformation. One of the most common forms of a track fragment destruction is the loss of foundation support (one or several neighbouring sleepers) resulting from the indentation of the ballast material in the subgrade. The pressure of a vehicle passing through a damaged section of the track causes the so-called dynamic track irregularity. The impact of dynamic track vertical irregularity on the values of wheel-rail contact forces of a passing vehicle was investigated. The model of the passenger wagon-track system was created using the VI-Rail tool. The vehicle motion on curves with different values of track radius and superelevations was investigated. Vertical track irregularities occur on the internal rail only. The lengths of the track irregularity correspond to one, two or three sleepers unsupported on one side. The test results are presented in the form of diagrams and referred to applicable standards and regulations.

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 new time-delayed periodic boundary condition for discrete element modelling of railway track under moving wheel loads

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Huiqi Li ◽  
Glenn McDowell ◽  
John de Bono
Keyword(s):  
Boundary Condition ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Discrete Element ◽  
Contact Forces ◽  
Railway Track ◽  
Discrete Element Modelling ◽  
Fixed Boundary ◽  
Element Modelling ◽  
New Time

Abstract A new time-delayed periodic boundary condition (PBC) has been proposed for discrete element modelling (DEM) of periodic structures subject to moving loads such as railway track based on a box test which is normally used as an element testing model. The new proposed time-delayed PBC is approached by predicting forces acting on ghost particles with the consideration of different loading phases for adjacent sleepers whereas a normal PBC simply gives the ghost particles the same contact forces as the original particles. By comparing the sleeper in a single sleeper test with a fixed boundary, a normal periodic boundary and the newly proposed time-delayed PBC (TDPBC), the new TDPBC was found to produce the closest settlement to that of the middle sleeper in a three-sleeper test which was assumed to be free of boundary effects. It appears that the new TDPBC can eliminate the boundary effect more effectively than either a fixed boundary or a normal periodic cell. Graphic abstract

Sign in / Sign up

Export Citation Format

Share Document