Railway track deflection analysis by using evolutionary algorithms

In contrast to numerical methods, analytical modelling of the railway track is one of the less time-consuming and computationally demanding methods which, in combination with the computing power commonly available today, can form an effective tool for analysing the behaviour of the railway track.This paper deals with the use of iterative methods of evolutionary algorithms, together with analytical modelling, for the purpose of reverse analysis of the measured deflection caused by moving loads acting on the railway track. The theoretical assumptions of the analytical model used, the data collection methodology and the method used for the reverse analysis are presented. The results of the analysis are also presented

The long-pitch corrugation development in small radii curves

The paper deals with the phenomenon of long-pitch corrugation in curves of the small radii and also the effects that accelerate or slow down its development. The paper presents data from sections of railway track measured for new rails, rails before and after grinding or replacement. The effect of train speeds running through the curves and the associated cant deficiency or excess were studied. The tendencies of long-pitch corrugation development are described, which can be used to estimate when maintenance action or rail replacement will be necessary

Comprehensive verification of the behavior of the continuous welded rail on the bridge

The aim of this paper is to verify the real behavior of the continuous welded rail on the bridge with a longer expansion length than allowed by Czech national regulations. Special attention is focused on the rate of interaction of the continuous welded rail and the bridge, which decisively affects the stress state in the continuous welded rail when the temperature changes. In order to improve the result and increase the accuracy of observation, two measuring methods (geodetic and strain gauge) were chosen while recording the temperature conditions of individual components of the system were simultaneously recorded

Neural Network-Based Train Identification in Railway Switches and Crossings Using Accelerometer Data

This paper aims to analyse possibilities of train type identification in railway switches and crossings (S&C) based on accelerometer data by using contemporary machine learning methods such as neural networks. That is a unique approach since trains have been only identified in a straight track. Accelerometer sensors placed around the S&C structure were the source of input data for subsequent models. Data from four S&C at different locations were considered and various neural network architectures evaluated. The research indicated the feasibility to identify trains in S&C using neural networks from accelerometer data. Models trained at one location are generally transferable to another location despite differences in geometrical parameters, substructure, and direction of passing trains. Other challenges include small dataset and speed variation of the trains that must be considered for accurate identification. Results are obtained using statistical bootstrapping and are presented in a form of confusion matrices

Train Type Identification at S&C

The presented paper concerns the development of condition monitoring system for railroad switches and crossings that utilizes vibration data. Successful utilization of such system requires a robust and efficient train type identification. Given the complex and unique dynamical response of any vehicle track interaction, the machine learning was chosen as a suitable tool. For design and validation of the system, real on-site acceleration data were used. The resulting theoretical and practical challenges are discussed

Sensitivity enriched multi-criterion decision making process for novel railway switches and crossings - a case study

Background: Despite their important role in railway operations, switches and crossings (S&C) have changed little since their conception over a century ago. It stands now that the existing designs for S&C are reaching their maximum point of incremental performance improvement, and only a radical redesign can overcome the constraints that current designs are imposing on railway network capacity. This paper describes the process of producing novel designs for next generation switches and crossings, as part of the S-CODE project. Methods: Given the many aspects that govern a successful S&C design, it is critical to adopt multi criteria decision making (MCDM) processes to identify a specific solution for the next generation of switches and crossings. However, a common shortcoming of these methods is that their results can be heavily influenced by external factors, such as uncertainty in criterium weighting or bias of the evaluators, for example. This paper therefore proposes a process based on the Pugh Matrix method to reduce such biases by using sensitivity analysis to investigate them and improve the reliability of decision making. Results: In this paper, we analysed the influences of three different external factors, measuring the sensitivity of ranking due to (a) weightings, (b) organisational and (c) discipline bias. The order of preference of the results was disturbed only to a minimum while small influences of bias were detected. Conclusions: Through this case study, we believe that the paper demonstrates an effective case study for a quantitative process that can improve the reliability of decision making

Dynamical response of railway switches and crossings

A procedure for the numerical analysis of the dynamic response during the passage of railway vehicles is described. The solution is based on the finite element method (FEM), which is used for the calculation of track stresses. An FEM model was used with a fine structure that included all components of switches and crossings, including movable parts. The excitation forces are defined on the basis of the assumed interaction between track and vehicle. The track stiffness defined by FEM analyses is used for the calculation of dynamic vertical and lateral wheel load. A special model of a railway vehicle was built with the aim of calculating the forces at points where abrupt stiffness changes occur, as well as geometrical imperfections in the frog structure