Stasys Dailydka

Modelling the interaction between railway wheel and rail

The article presents a mathematical model for assessing the real operating conditions of railway rolling stock, taking into account the situations when the wheel loses contact with rail. The obtained amplitudinal fluctuation characteristics depend on the set roughness function and the running speed of the wheel. When calculating dynamic processes, the contact between wheel and rail should be considered unstable. With the increase of speed, the impact of this instability increases.

Determination of the dynamic characteristics of freight wagons with various bogie

In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the vertical Kvd and horizontal Khd dynamic coefficients as well as the stability coefficient Ks, which determines the wheel flange resistance to derailment. The article compares dynamic indications for three different types of bogies. There were no tangible differences observed for all the three different types of bogies running at a speed of 40 to 120 km/h on a direct tangent rail section. Nevertheless, there is a realistic potential to improve the dynamic indicators of a freight wagon by rationalising suspension unit parameters.

An Analytical Mathematical Method for Calculation of the Dynamic Wheel–Rail Impact Force Caused by Wheel Flat

ABSTRACT The simplified method to determine a vertical impact force of wheel with flat and rail interaction is presented in this article. The presented simplified method can be used to identify maximum contact force and its distribution in the contact length between the damaged wheel and the rail. The vertical impact force depends on geometrical parameters of the rail and wheel with flat, speed of vehicle and the angle of deviation of rail. This article demonstrates the influence of wheel with flat geometrical parameters, speed of vehicle to maximum contact force and its distribution in the contact zone. The obtained values of the simplified method for determination of a vertical contact force are compared with the results obtained from field measurements.

THE ASPECT OF VECTOR CONTROL USING THE ASYNCHRONOUS TRACTION MOTOR IN LOCOMOTIVES

Abstract The article examines curves controlling asynchronous traction motors increasingly used in locomotive electric drives the main task of which is to create a tractive effort‐speed curve of an ideal locomotive Fk = f(v), including a hyperbolic area the curve of which will create conditions showing that energy created by the diesel engine of diesel locomotives (electric locomotives and in case of electric trains, electricity taken from the contact network) over the entire range of locomotive speed is turned into efficient work. Mechanical power on wheel sets is constant Pk = Fkv = const, the power of the diesel engine is fully used over the entire range of locomotive speed. Tractive effort‐speed curve Fk(v) shows the dependency of locomotive traction power Fk on movement speed v. The article presents theoretical and practical aspects relevant to creating the structure of locomotive electric drive and selecting optimal control that is especially relevant to creating the structure of locomotive electric...

The dynamic behaviour of a wheel flat of a railway vehicle and rail irregularities

The article examines a mathematical model for the system ‘Railway Vehicle Wheel–Track’ that allows examining the interaction between a wheel flat and a rail in the vertical plane. The dynamics of the railway track is described using the finite element method while that of the soil and vehicle is expressed applying discrete elements. The model is used for assessing physical and mechanical properties, the roughness of the wheel, rail surface and their geometry. The analysis of the dynamic system ‘Railway Vehicle Wheel–Track’ has been conducted. In accordance with the revised method, forces arising from contact between the wheel flat and the rail are possible to be determined in a more precise way. The article presents and analyses the results of a mathematical experiment on this system.

Research of energy efficiency and reduction of environmental pollution in freight rail transportation

AbstractThe publication presents the results arising from the experimental and mathematical modelling studies, which mainly aimed to investigate the selection and optimization of the rational operation modes particular to diesel engines of freight locomotives in the possession of the JSC ‘Lithuanian Railways’ (AB ‘Lietuvos geležinkeliai’). The goal of the optimization is to increase the energy efficiency, reduce fuel consumption and emissions of harmful air pollutants to the environment from diesel engines of locomotives during freight transportation via the main lines of the Lithuanian railway network. A complex energy efficiency and environmental pollution assessment criterion KE–E adjusted for diesel engines of freight locomotives has been suggested. The use of KE–E on the basis of the conducted complex experimental mathematical computer modelling studies has determined that the reserves reducing fuel consumption, harmful emissions and greenhouse gas (CO2) emissions constitute 6÷15% on an average, and ...

The Aspects of Modernization of Diesel-Electric Locomotives and Platform for Transportation of Railway Switches in Lithuanian Railways

Electrical locomotives made in Russia, Czechoslovakia and Ukraine have been used primarily in the railways of the former Soviet Union. Russian companies have manufactured the TEM1 and TEM2 diesel-electric shunting locomotives and the TEP-60 and TEP-70 passenger locomotives, while the 2M62 freight locomotives have been manufactured in Ukraine. The CME2 and CME3 shunting diesel-electric locomotives, manufactured in Czechoslovakia, were manufactured with analogous control systems of the entire powertrain and electric drive, which have many deficiencies, the most important of which is high fuel consumption. Reducing power transmission losses from the primary power source—the diesel engine—to the wheel sets is critical. JSC Lietuvos geležinkeliai, who owns a fleet of TEM2 and CME3 typical shunting locomotives, 2M62 freight locomotive and TEP-70 passenger locomotive, made the decision to modernize them. To this end, JSC Lietuvos geležinkeliai established a subsidiary company, Vilniaus lokomotyvų remonto depas UAB, where locomotives were modernized and new locomotives were manufactured for JSC Lietuvos geležinkeliai and railways abroad during the period 2005–2015. Modernization was performed together with scientists from Vilnius Gediminas Technical University (VGTU). Companies participating in the modernization effort included Vilniaus lokomotyvų remonto depas UAB, Czech company CZ Loko a.s., CJSC TMHB Transmashholding, the Briansk machine building plant (Russia), Transmashholding, Caterpillar, MTU, and the Hungarian company Woodward-Mega Kft, among others.

USE OF “KNOWLEDGE HOUSE”, DWS, DMS AND DSS METHODOLOGY BY COMPLETING A COMPETITORS' ANALYSIS IN THE RAILWAY SECTOR

In completing a competitors’ analysis in the railway sector by using the “Knowledge House” method, there is frequently a problem of data and information accessibility. The quality of primary information has direct influence on the quality of analytical conclusions. One more condition for the qualitative application of this method is the intellectual capital and experience of the analyst. One should note that in this regard we face another problem, that of selection of proper personnel, on the qualification of whom depends the accuracy of the evaluation and final results, on the basis of which strategic decisions are taken. The main aim of the paper is to assess the opportunities for applications of competitive intelligence methods in the railway sector. The study is using “Knowledge House”, DWS, DMS, DSS methodologies.Having analysed the scientific works the direct scientific sources of information, which are oriented to the application of the methods of competitive intelligence to the railway sector, have not been identified. The paper is absolutely original in that until now the competitive intelligence techniques have not been applied for the railway sector companies.Considering the fact that foreign companies, which compete for freighting at the international level, are regarded as the main competitors of the railway sector, the use of the methods of the competitive intelligence becomes more important while fighting for the part of the market. The competitive intelligence methods and their application to the railway sector companies are little studied. In accordance with application of the relevant methods in other sectors, it can be assumed that these innovative approaches could have a positive impact on the competitiveness of companies in the railway sector and their income.