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.

scholarly journals A Review of Different Aspects of Applying Asphalt and Bituminous Mixes under a Railway Track

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 169
Author(s):  
Kazem Jadidi ◽  
Morteza Esmaeili ◽  
Mehdi Kalantari ◽  
Mehdi Khalili ◽  
Moses Karakouzian
Keyword(s):  
High Speed ◽  
Review Paper ◽  
Railway Track ◽  
High Speed Train ◽  
Slab Track ◽  
Bituminous Mixtures ◽  
Railway Tracks ◽  
Potential Applications ◽  
Heavy Loads ◽  
Design And Construction

Asphalt is a common material that is used extensively for roadways. Furthermore, bituminous mixes have been used in railways, both as asphalt and as mortar. Different agencies and research institutes have investigated and suggested various applications. These studies indicate the benefits of bituminous material under railways, such as improving a substructure’s stiffness and bearing capacity; enhancing its dynamic characteristics and response, especially under high-speed train loads; waterproofing the subgrade; protecting the top layers against fine contamination. These potential applications can improve the overall track structure performance and lead to minimizing settlement under heavy loads. They can also guarantee an appropriate response under high-speed loads, especially in comparison to a rigid slab track. This review paper documents the literature related to the utilization of asphalt and bituminous mixes in railway tracks. This paper presents a critical review of the research in the application of asphalt and bituminous mixes in railway tracks. Additionally, this paper reviews the design and construction recommendations and procedures for asphalt and bituminous mixes in railway tracks as practiced in different countries. This paper also provides case studies of projects where asphalt and bituminous mixes have been utilized in railway tracks. It is anticipated that this review paper will facilitate (1) the exchange of ideas and innovations in the area of the design and construction of railway tracks and (2) the development of unified standards for the design and construction of railway tracks with asphalt and bituminous mixtures.

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.

scholarly journals Buckling Analysis of Interspersed Railway Tracks

2020 ◽  
Vol 10 (9) ◽  
pp. 3091 ◽  
Author(s):  
Chayut Ngamkhanong ◽  
Chuah Ming Wey ◽  
Sakdirat Kaewunruen
Keyword(s):  
Global Climate ◽  
Extreme Temperature ◽  
Railway Track ◽  
Significant Deterioration ◽  
Track Geometry ◽  
Railway Tracks ◽  
Life Cycle Design ◽  
Continuous Welded Rail ◽  
Natural Decay ◽  
Construction Strategies

Nowadays, timber sleepers are still used for ballasted railway tracks to carry passengers and transport goods. However, the process of natural decay causes the problem of timber sleeper degradation over time. A temporary “interspersed” approach is used to replace rotten timbers with concrete sleepers. This implementation has several inadequacies, as interspersed railway tracks have inconsistent stiffness and experience significant deterioration over the years. Increased heat due to the change in the global climate can induce a compression force in the continuous welded rail (CWR), leading to a change in track geometry called “track buckling”. A literature review shows that track buckling on plain tracks has been widely studied. However, the buckling of interspersed tracks has not been fully studied. This study presents 3D finite element modelling of interspersed railway tracks subjected to temperature change. The effect of the boundary conditions on the buckling shape is considered. The obtained results show that the interspersed approach may reduce the likelihood of track buckling. This study is the world’s first to investigate the buckling behaviour of interspersed railway tracks. The insight into interspersed railway tracks derived from this study will underpin the life cycle design, maintenance, and construction strategies related to the use of concrete sleepers as spot replacement sleepers in ageing railway track systems. The outcome of this study will help track engineers to improve the inspection of the lateral stiffness of interspersed tracks in areas prone to extreme temperature.

Application of polyurethane geocomposites to help maintain track geometry for high-speed ballasted railway tracks

2012 ◽  
Vol 13 (11) ◽  
pp. 836-849 ◽  
Author(s):  
Peter Keith Woodward ◽  
Abdellah El Kacimi ◽  
Omar Laghrouche ◽  
Gabriela Medero ◽  
Meysam Banimahd
Keyword(s):  
High Speed ◽  
Track Geometry ◽  
Railway Tracks

On the Effects of the USP on the Lateral Resistance of Ballasted Railway Tracks

2018 ◽  
Author(s):  
Giovanni Pio Pucillo ◽  
Antonio De Iorio ◽  
Stefano Rossi ◽  
Mario Testa
Keyword(s):  
High Speed ◽  
Maintenance Costs ◽  
Speed Reduction ◽  
Track Geometry ◽  
Vertical Stiffness ◽  
Railway Tracks ◽  
Lateral Resistance ◽  
Lateral Plane ◽  
Track Vertical Stiffness ◽  
Proper Values

From the advent of high-speed (HS) railways and with increasing traffic-induced loads transmitted to the superstructure, maintenance costs due to track geometry degradation have become a crucial problem for researchers and railway administrations. Moreover, the operations of ballast renewal, track tamping, and track re-alignment, that are indispensable to guarantee a good track geometry, have dramatic effects on the tie-ballast lateral resistance, which in turn reduce the track flexural strength in the lateral plane and increase the proneness of railway tracks made of continuous welded rails (CWR) to experience either progressive lateral shift of the track panel or thermal track buckling phenomena. To restore proper values of the tie-ballast lateral resistance, railway technicians either impose a speed reduction or compact the ballast bed mechanically by mean of the dynamic track stabilizing machines. Recently, elastic elements in railway tracks are receiving more and more attention due to their ability to reduce track geometry degradation and to attenuate noise and vibrations. Under Tie Pads, or Under Sleeper Pads (USP), guarantee better homogenization of the track vertical stiffness and have received more attention due to their ability to reduce maintenance costs. Most published studies focused their attention to USPs’ attitude to improve track performances in terms of dynamic impact force mitigation and track quality improvement; however, with few exceptions, no available literature exists on lateral resistance of ballasted track with USP, and some question still remains whether or not the lateral resistance is improved by USP. In this study, the experimental results of about 40 lateral resistance tests carried out in situ are reported and discussed. The tests were performed with the Discrete Cut Panel Pull Test (DCPPT) technique on three type of concrete ties, with and without USP; each type of tie and the related track conditions (ballast thickness, subgrade thickness and composition, shoulder width, ballast wall, etc.) were representative of specific track conditions, namely traditional tracks, high-speed lines and gallery. The tests were carried out in loaded and unloaded track conditions, in compacted and just-laid track conditions. In compacted ballast conditions the peak lateral resistance due to USPs can increase up to 20% — depending on the material used — and this variation is almost constant in the bedding modulus range considered in this study, which was quite well representative of typical static bedding modulus values of actual USPs. Even higher advantages seem to be achievable with softer USPs in weak or just-tamped ballast conditions.

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.

Effect of Long-Term Bridge Deformations on Safe Operation of High-Speed Railway and Vibration of Vehicle–Bridge Coupled System

2019 ◽  
Vol 19 (09) ◽  
pp. 1950111 ◽  
Author(s):  
Hongye Gou ◽  
Longcheng Yang ◽  
Zhixiang Mo ◽  
Wei Guo ◽  
Xiaoyu Shi ◽  
...  
Keyword(s):  
High Speed ◽  
Measurement Data ◽  
Coupled System ◽  
Bridge Pier ◽  
Railway Track ◽  
Vertical Acceleration ◽  
High Speed Train ◽  
High Speed Trains ◽  
Track Deformation

Operation safety of high-speed trains is dependent on their vibration characteristics, which vary with bridge deformation. This paper studies the influence of bridge pier settlement and girder creep camber, which are two typical types of long-term bridge deformation, on the vibration of high-speed trains. To this end, an analytical approach is presented to link the bridge deformation with railway track deformation; the track deformation is used to analyze the vibration of the CRH2 high-speed train in China. The vibration analysis results are validated using the in-situ measurement data. The present study shows that bridge pier settlement greatly affects the vertical acceleration, derailment coefficient and wheel unloading rate of the high-speed train; incorporating bridge girder camber aggravates the vibration of the train–bridge system. The threshold of bridge pier settlement is suggested to be 11.1[Formula: see text]mm for trains moving at 350[Formula: see text]km/h with regard to the code-specified vibration limit. This study has significant implications for the design and operation of high-speed railways.

scholarly journals Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

2020 ◽  
Vol 28 (3) ◽  
pp. 213-231
Author(s):  
Wanming Zhai ◽  
Kaiyun Wang ◽  
Zhaowei Chen ◽  
Shengyang Zhu ◽  
Chengbiao Cai ◽  
...  
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Full Scale ◽  
Functional Test ◽  
Railway Track ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Railway Infrastructure ◽  
Test Platform

Abstract Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure, a full-scale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper, and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples. Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways, namely the CRTS I, the CRTS II and the CRTS III ballastless tracks, the double-block ballastless track and the ballasted track, the test platform is established strictly according to the construction standard of Chinese high-speed railways. Three kinds of effective loading methods are employed, including the real bogie loading, multi-point loading and the impact loading. Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement, acceleration, pressure, structural strain and deformation, etc. Utilizing this test platform, both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated, being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways. As examples, three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways. Some interesting phenomena and meaningful results are captured by the developed test platform, which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

scholarly journals Railway track design & degradation

2018 ◽  
Vol 211 ◽  
pp. 11006
Author(s):  
Mehran Sadri ◽  
Tao Lu ◽  
Arjen Zoeteman ◽  
Michaël Steenbergen
Keyword(s):  
Degradation Rate ◽  
Early Stage ◽  
Mechanical Energy ◽  
Measurement Data ◽  
Empirical Models ◽  
Railway Track ◽  
Structural Performance ◽  
Design Parameters ◽  
Railway Tracks

The long-term behaviour of railway track has attracted increasing attention in recent years. Improvements in long-term structural performance reduce demands for maintenance and increase the continuous availability of railway lines. The focus of this paper is on the prediction of the sensitivity of a track design to long-term deterioration in terms of track geometry. According to the state of the art literature, degradation is often investigated using empirical models based on field measurement data. Although a rough maintenance forecast may be made employing empirical models, the predictions are not generic, and the physical processes which govern track degradation under train operation remain unclear. The first aim of this study is to present a mathematical model to elucidate the underlying physics of long-term degradation of railway tracks. The model consists of an infinitely long beam which is periodically supported by equidistantly discrete sleepers and a moving unsprung mass which represents a travelling train. The mechanical energy dissipated in the substructure is proposed to serve as a measure of the track degradation rate. Secondly, parametric studies on energy dissipation are conducted to identify effects of various track design parameters on the susceptibility of the track to degradation, as well as the effect of the train speed. It has been shown that the track/subgrade stiffness is the most influential parameter on degradation whereas other system parameters do influence the degradation rate but at lower magnitudes. The conclusions can be used to optimise the track design in the early stage for better long-term structural performance of railway tracks.

scholarly journals Optimization of work performance of snow removal work trains on the basis of linear programming

2018 ◽  
Vol 239 ◽  
pp. 04001 ◽  
Author(s):  
Aleksey Manakov ◽  
Andrey Abramov ◽  
Andrey Ilinykh ◽  
Vladimir Aksenov
Keyword(s):  
Linear Programming ◽  
Work Performance ◽  
Railway Track ◽  
Rolling Stock ◽  
Snow Removal ◽  
Track Maintenance ◽  
Maintenance Work ◽  
Optimization Methodology ◽  
The Cost ◽  
Removal Equipment

The introduction of monitoring systems for the work performance of special rolling stock and monitoring the load of snow removal work trains revealed a number of shortcomings in the planning, organization, and recording of work performed by snow removal work trains. The elimination of the identified problems is possible on the basis of optimization of work performance, the implementation of which can be achieved on the basis of existing systems with appropriate additional functionality. For this purpose, in the framework of the theoretical studies presented in the paper, a methodology for optimization of work performance of snow removal work trains has been developed. Linear programming is adopted as a method of solving the optimization problem. On the basis of the algorithm for solving the transport problem, the problem of minimizing the cost of snow removal from various sections of the track by the existing park of work trains is formulated, for which a mathematical model is constructed that includes the objective function and the corresponding restrictions. The results of the study show that the widespread use of work planning on the basis of the presented optimization methodology will make it possible to make the most efficient use of snow removal equipment and, as a result, to reduce the cost of this type of railway track maintenance work.

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