Visual measurement system for wheel–rail lateral position evaluation

Railway infrastructure must meet safety requirements concerning its construction and operation. Track geometry monitoring is one of the most important activities in maintaining the steady technical conditions of rail infrastructure. Commonly, it is performed using complex measurement equipment installed on track-recording coaches. Existing low-cost inertial sensor-based measurement systems provide reliable measurements of track geometry in vertical directions. However, solutions are needed for track geometry parameter measurement in the lateral direction. In this research, the authors developed a visual measurement system for track gauge evaluation. It involves the detection of measurement points and the visual measurement of the distance between them. The accuracy of the visual measurement system was evaluated in the laboratory and showed promising results. The initial field test was performed in the Vilnius railway station yard, driving at low velocity on the straight track section. The results show that the image point selection method developed for selecting the wheel and rail points to measure distance is stable enough for TG measurement. Recommendations for the further improvement of the developed system are presented

Study of traction rolling-stock using in Lithuanian sector of railway line "Rail Baltica"

The article analyses the current traction rolling-stock used by „Lietuvos geležinkeliai“ Plc. for freight transportation. The technical data of the above mentioned rolling-stock is explored and compared, and operation costs are estimated in the article. After the assessment of the forecasts of freight flows on the constructed railway „Rail Baltica“, the algorithm for selection of freight locomotives was proposed. The efficiency of the locomotives operated on the railway is determined by three multicriteria evaluation methods: the sum of ratings, simple additive weighting, and the geometric mean method. Locomotives are valued in accordance with technical, economic and ecological parameters. The results of possible effective performance of the rolling stock have been determined by changing coefficient values of the criteria. Finally, basic conclusions are given

Peculiarities of traction forces in wheel/rail contact area

Traction force and train movement stability dependence on division of forces involved in wheel/rail contact area are the main subjects of this article. The influence of wheel/rail contact properties in the vehicle dynamics and adhesion fields is investigated. Current tendency all over the world is to reduce the conicity of wheels with the aim of increasing the speed of trains. Wave-length of moving wheel-set in track for worn wheel-set tyre is twice less than for new wheel running profile

МАТЕМАТИЧНЕ МОДЕЛІ ДИНАМІЧНОЇ ВЗАЄМОДІЇ МІЖ КОЛЕСАМИ І РЕЙКОВИМ ШЛЯХОМ

The main goal of this paper is to show how the effects of maximum bending tensions at different locations in the track caused by simultaneous changes of various parameters can be estimated in a rational manner. The dynamics of the vertical interaction between a moving rigid wheel and a flexible railway track is investigated. An asymmetric linear three-dimensional beam structure model of a finite length of the track is suggested. The influence of eight selected track parameters on the dynamic behaviour of the track is investigated. A two-level fractional factorial design method is used in the search for the combination of numerical values of these parameters minimizing themaximum bending tensions.В статье показано влияние моделируемых параметров, которые учитываются рациональным способом с применением фракционного факториала двух уровней на распределение напряжений в различных местах рельсового звена. Представлен анализ вертикальной динамики взаимодействия жесткого колеса с рельсом. С целью минимизации напряжений рельса производится поиск оптимального варианта комбинации множества влияющих параметров с применением метод фракционного факториала двух уровней.У статті показаний вплив моделюючих параметрів, що враховуються раціональним способом, застосовуючи фракційний факторіал двох рівнів, на розподіл напружень у різних місцях рейки. Представлено аналіз вертикальної динаміки взаємодії твердого колеса з рейкою. З метою мінімізації напружень рейки шукається оптимальний варіант комбінації безлічі параметрів із застосуванням методу фракційного факторіала двох рівнів.

Исследование динамической стабильности движения грузового вагона при изменениях жесткости железнодорожного пути

Authors analysed the rail dynamic models of rail vehicle and surveyed the features of the system “vehicle-track” modelling. Algorithms of creep forces calculation were examined. Four-axle freight wagon movement on the straight track and on curves corresponding to the given vertical and transversal track irregularities was modelled by software tool "Universal Mechanism". Authors examined the track stiffness influence on the vehicle moving stability/safety parameters at different speed, vehicle weight and track irregularities considering different wear rail profiles. Finally, basic conclusions and recommendations are given.Авторы проанализировали динамические модели рельсовых экипажей и рассмотрели особенности моделирования системы «вагон-путь». Рассмотрены алгоритмы расчета сил крипа. С помощью программного пакета «Универсальный механизм» было смоделировано движение четырехосного грузового вагона по прямой трассе и по кривой с учетом вертикальных и горизонтальных неровностей рельсовых нитей. Авторы исследовали влияние жесткости железнодорожного пути на параметры стабильность/безопасность движения рельсового экипажа, движущегося с разной скоростью, с разной массой вагона и с учетом профилей рельсов различного износа. В конце сформулированы основные выводы и рекомендации

Podejście do modelowania stałego procesu międzyawaryjnego odnowy wieloelementowej floty pasażerskiej

While railway companies operate rolling-stock, a substantial part of its expenses goes to maintenance and repair. However, the amount of repair works is directly proportional to the average age of a rolling-stock fleet or its reliability. When renewal an existing fleet of a few dozen rolling-stocks, the installation of the new vehicles reduces the overall failure amount of the fleet proportionally to the number of acquired vehicles. This article provides a concept for creating the model of a passenger rollingstock's failure intensity according to the mileage. According to this model, a vehicle fleet renewal algorithm can be created and used in order to limit the fluctuation of the fleet's average failure intensity as much as possible and to achieve the most accurate correlation between the number of failures and the fleet's average mileage. Thus a railway company has an opportunity to avoid the unplanned expenses for repairing the vehicles during the unforeseen failure peaks. The SPLINE method is proposed in order to indicate the vehicle failure flow's dependency on the vehicle mileage. After using this method to indicate the variation of the fleet's constant interfailure according to the mileage, the fleet's failure intensity can be modelled according to the algorithm of installing the acquired vehicles for operation.Znaczna część wydatków ponoszonych przez przedsiębiorstwo kolejowe z tytułu eksploatacji taboru kolejowego, to wydatki na konserwację i naprawy. Jednakże, należy pamiętać, że liczba prac remontowych jest wprost proporcjonalna do średniego wieku floty taboru lub jej niezawodności. Przy odnawianiu istniejącej floty kilkudziesięciu pojazdów kolejowych, wprowadzenie nowych pojazdów zmniejsza ogólną ilość awarii floty proporcjonalnie do liczby nowo nabytych pojazdów. W artykule przedstawiono koncepcję stworzenia modelu intensywności uszkodzeń taboru pasażerskiego w funkcji przebiegu kilometrowego. Zgodnie z tym modelem, można stworzyć algorytm odnowy floty pojazdów, z wykorzystaniem którego można maksymalnie ograniczyć wahania średniej intensywności uszkodzeń floty oraz osiągnąć najbardziej dokładną korelację między liczbą uszkodzeń a średnim przebiegiem pojazdów floty. W ten sposób przedsiębiorstwo kolejowe ma szansę uniknąć nieplanowanych wydatków na naprawy pojazdów podczas nieprzewidzianych okresów wzmożonej awaryjności. Zaproponowano metodę SPLINE, za pomocą której można określić zależność awaryjności pojazdu od jego przebiegu kilometrowego. Zastosowanie tej metody pozwala ustalić zmiany w stałym procesie międzyawaryjnym zależne od przebiegu, co z kolei pozwala na modelowanie intensywności uszkodzeń floty według algorytmu wprowadzania nowo nabytych pojazdów do eksploatacji

The study of schoolchildren transportation efficiency in Lithuania

The system of transportation of schoolchildren should also be transformed with the aim of more rational use of resources and vehicles taking children in and out of schools. Rational structure of school network and a system of children transportation will help to save the money allocated on education as well as to ensure various educational services, taking into account social, economic, cultural and demographic changes. The research revealed considerable differences in operational costs of school buses in Lithuania. To account for this spread of values (up to 5 times), a more detailed analysis is needed. Considerable spread of operational costs of buses is questionable because they are in a good (or perfect) technical state. The repay time of the bus depends on the difference between the cost of carrying students by private and public transport covered by local government institutions and the relative expenses of busing a student per one kilometer by buses

Investigation of vehicle stability on road curves in winter conditions

The paper reveals peculiarities of a vehicle movement/operation on road curves when the road surface is slippery and/or snowy, with asphalt ruts. The survey of scientific works related to the lateral acceleration and movement dynamics of a vehicle is presented. Field experiments with different vehicles were carried out in winter conditions. The acceleration value and stability parameters depending on the speed of a vehicle and adhesion coefficient on road curves are analysed. Dependence of the vehicle lateral acceleration on road curves with various adhesion surfaces are given in graphical charts. Recommendations how to improve road safety by limitation of the speed in winter conditions are formulated. Finally, basic conclusions are given. Handling the vehicle on the road with the compressed snow surface (on the curve of the radius of 120 m) is much more dangerous when the adhesion coefficient of the wheels and the road is low if compared to handling the vehicle along the dry ruts at the same speed. When the vehicle moves along the curve of 120 m radius at a speed of 70 km/h, and the road surface is snowy, the lateral acceleration of 3.1 m/s2 is reached. The paper indicates that lateral acceleration of 3.1 m/s2 can be reached while moving along the snowy road with dry ruts at a speed higher in 27% (90 km/h). For improving the vehicle safety, it is recommended to have road signs on sharp turns/curves (R less than 120 m) to decrease the vehicle speed in 20 km/h