ASSESSMENT OF RAILWAY LINES: AN EFFICIENCY RATING ANALYSIS FOR BALTIC COUNTRIES

The article investigates a possibility of using the traditional multi-criteria assessment methods to evaluate how significance of a railway line is distributed for the countries it crosses. The article analyses two examples of railway lines: the railway line Rail Baltica (Poland, Lithuania, Latvia and Estonia) and the container train Viking route (Lithuania, Belarus and Ukraine). When investigating for which countries the Rail Baltica project will have bigger significance, and for which smaller, indicators of the countries are analysed by the length of Rail Baltica in the country, length falling per million residents in the country, length falling per thousand km of the existing railway, length per area of the county and length falling per country’s gross domestic product (GDP). To generalize them, multi-criteria optimization methods, such the geometric mean method, were used. To answer the question whether the methodology used is adequate, it was tested using the example of the already operating container train Viking. The results of calculations for the previously mentioned criteria are combined with the actual distribution of the freight turnover. A positive conclusion is made about the adequacy of the methodology to assessment of the importance of the railway line for the country

A survey of methods used for assessing the performance of diesel locomotives

The present paper is aimed at evaluating the methods used for determining the performance of Diesel locomotives. Therefore, two main approaches to assessing the locomotive performance can be distinguished: a method based on individual indicators; a method based on an integrated indicator. The analysis of the available methods for complex evaluation of the locomotive condition has shown that overall performance of the locomotive can be described by a dimensionless indicator. In determining the state of Diesel locomotives, researchers rely on the criteria commonly used in assessing the performance of any machine. They are as follows: technical, economical, functional (operational). First Published Online: 27 Oct 201

Analysis of passenger rolling stock faults and its statistics in Lithuania

Performed data analysis aims to determine the number of rolling stock breakdowns and how it depends on rolling stock age, the number of passengers and operations. The mathematical model, stated below, analyses correlation between passenger fleet upgrade intensity and the number of faults. When planning to buy some new rolling stock (3÷6 wagons electric or diesel trains) while using this model, the number of faults can be predicted up to five years

Investigating the dynamics of passenger rolling stock deterioration

One of the major economic criteria is associated with the growth of maintenance costs of old rail vehicles. The research aims to determine the ageing criteria of passenger rolling stock, which could take into account fuel, diesel oil and repair costs. Therefore, economic criteria based on the above costs are generated and their comparative analysis is made. The research object is Vilnius locomotive depot. First published online: 27 Oct 201

Method of spectral analysis of traction current of AC electric locomotives

An improved method for spectral analysis of traction current of an Alternating Current (AC) electric locomotive is considered in the article. A new method of spectral analysis considers the change in voltage in the catenary system as a non-deterministic, non-ergodic and non-Gaussian process. It has been established that higher voltage harmonics in the catenary system have a significant negative effect on the operation of non-traction railway consumers of electricity. In addition, electric locomotives operating in the same feeder zone have a mutual influence on each other. Electric railway transport is a source of higher voltage harmonics and strongly distorts the shape of the sinusoidal voltage of the catenary system, which are caused by the higher spectral components of the current in the electric locomotive traction drive circuit. These spectral components of the traction current arise in the traction drive circuit due to the nonlinearity of the current-voltage characteristics of the electronic devices of an electric locomotive, for example, a contact rectifier, a capacitor circuit of traction motors. Reactive power compensators are used in electric locomotives to eliminate components of higher harmonic traction current in the catenary system. Traditionally, spectral analysis in such systems is performed using Fourier methods. However, the determination of the spectral components of the traction current by the Fourier method for constructing a control system for a reactive power compensator is possible only if the process of voltage variation is a deterministic or ergodic Gaussian process. Otherwise, the application of Fourier transform methods will be incorrect. An analysis of the factors that affect voltage changes in the catenary system showed that this process is significantly different from the ergodic Gaussian process. Such factors include the following: the operating mode of the electric locomotives; number and total capacity of electric locomotives in one feeder zone; electric locomotives passing through feeder zones; instability of collection current. Thus, in the case under consideration, the application of the Fourier methods is incorrect for the analysis of the spectral components of the traction current. This affects the quality of compensation of the higher harmonic components of the traction current, and in some cases, the unstable operation of the control system of the active part of the reactive power compensator. Proposed scientific approach is based on the Levinson–Durbin linear prediction algorithm. On the one hand, this allows adapting the control system of the compensator to the voltage parameters of the catenary system. On the other hand, this allows taking into account the operating modes of electric rail vehicle with reactive power compensation. The construction of a compensator control system using the Levinson–Durbin algorithm significantly simplifies thensynchronization scheme of the compensator and power circuits of the traction electric drive of AC electric locomotive. A comparison of the traditional method of spectral analysis, based on the Fast Fourier Transform (FFT), and the method, based on the Levinson–Durbin algorithm, proposed by the authors, showed the high efficiency of the latter. First published online 21 January 202

Investigation into the mechanical properties and metal creaks of a diesel locomotive wheel

After JSC ‘Lithuanian Railways’ (AB ‘Lietuvos geležinkeliai‘) bought new Siemens ER20 CF locomotives produced in Western Europe and brought them into service, some of them have already done about 170–200 thousand km that caused the appearance of indentations of an inadmissible size (the depth is more than 3 mm, the length – 10 mm) the elimination of which turning cutting results in up to 20 mm loss of a wheel. Having grounded off the metal layer of indentation depth, indentation reappears (metal ‘flakes off') and needs to be removed by returning cutting the wheel. The purpose of the current investigation is to determine whether there is a reason to claim that the cause of wheel surface crumbling could be a chemical composition of the wheel or wheel‐to‐rail hardness ratio. The carried out investigations have revealed that there is no reason to claim that the cause of wheel surface crumbling could be the chemical composition of the wheel or wheel‐to‐rail hardness ratio. First published online: 10 Feb 201

STUDY ON THE PREDICTABILITY OF THE VERTICAL IMPACT OF RAIL VEHICLES RUNNING GEAR ON RAILS CONSIDERING WEATHER CONDITIONS AND WAGON SUSPENSION LOAD

The faulty running gear of rail vehicles can be identified by the results of measurements of vertical forces caused by wheel running surface damages or other wrongness of bogie suspension. Several different automatic diagnostic systems are used in European railways (operating while the trains are in service) to detect damage to rail-wheel running surfaces. The principles of this trackside equipment operation and the reliability of their measurements may differ noticeably. This is especially true in different seasons of the year (winter/summer). Data collection and aggregation results should be checked in equivalency (comparability). The authors compared the efficiency of different automatic systems in detecting wheel failures according to wheel-rail loads in different seasons of the year and presented their results. The authors also compared the similarity of results of the different measurement systems

INFLUENCE OF TRACK GEOMETRY CONDITION MONITORING ON RAILWAY INFRASTRUCTURE MAINTENANCE PROCESSING

This study analyzed the usage of data of track geometry measurement for railway infrastructure maintenance processing support and estimated its influence on railway infrastructure maintenance decision-making. Especially, the approach assessment of the influence of track geometry monitoring on railway infrastructure processing. The well-timed maintenance of the arrangement of railway tracks in allowable conditions is sufficient for the smooth and steady running of rail vehicles. The mechanism of track gauge widening during exploitation is usually gradual and relatively long-lasting. When are not detected in a timely manner, the final track failures often arise under the effect of additional factors, such as surpassed train speed limit, poorly maintained and functioning running gear of a rail vehicle, misalignment of rails, and extreme dynamical effects. A questionnaire considering the influence of the application of track geometry monitoring was formulated. An expert review was completed in order to perform a comparative analysis of the features of track geometry monitoring with the greatest influence on railway infrastructure maintenance processing. The data collected from respondents were processed using a multi-criterion estimation method, especially an interactive fuzzy linear assignment method. Finally, basic conclusions and considerations are given