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The 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 criterionKE–Eadjusted for diesel engines of freight locomotives has been suggested. The use ofKE–Eon 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 in the case of individual railway network lines they go up to 30%. The comparative emission of harmful components per fuel mass (NOx, CO, CH, PM) e′NOx,e′CO,e′CH,e′PMwhen carrying freight via the main lines of the railway network by trains weighing 3000÷7500 t has been singled out. The results constitute sufficient grounds to organise control of harmful emissions and provide an opportunity to solve practical tasks with a slight tolerance (3÷7%) taking account of diesel engines of locomotives used for transportation. It has been proposed to measure the freight transportation efficiency according to the complex criterionKE–E, indicates the energy efficiency and the assessment of environmental pollution originating from diesel engine of locomotives. The reserves for increasing the efficiency of energy usage have been studied according to the variational mathematical computer modelling data. A methodology for measuring the freight transportation rationality and estimating the optimal indicators has been proposed, using the values of theKE–Ecriterion for the railways freight transportation, as well as the technology for controlling the traction characteristics as well as energy and ecology indicators of diesel engines of locomotives in operational conditions. [ABSTRACT FROM PUBLISHER]

This article analyses the train traffic control systems in 1435 mm and 1520 mm gauge railways. The article analyses the aspects of train traffic control and locomotive energy saving by using the coordinates of track profile change that have been received from GPS. In the article, achievements of Lithuanian railways (LG) in the area of train traffic control optimisation are presented. [ABSTRACT FROM AUTHOR]

This paper analyzes the influence of transient operating modes in the Cat 3512B-HD and MTU 4000 R41 locomotive diesel engines on their energy usage. This analysis represents an integral component of the technological research and development performed at Lietuvos Geležinkeliai AB (JSC Lithuanian Railways) with the objective of increasing the efficiency of freight transportation with the upgraded 2M62M and modern ER20CF/2ER20CF diesel locomotives. The influence of transient modes on the operating variables of the locomotive diesel engines was evaluated under operational load-cycling conditions to aid in the selection of appropriate parameters (e.g., the train weight, the diesel locomotive type, and the technical characteristics of the diesel locomotive to be modeled) for freight transportation on Lithuanian railway lines. It was determined that the engine’s electronic control system compensates for the negative effects of transient operations on the engine’s energy usage. As a result, the increase in fuel consumption is less than 3% during transient operation when compared to steady-state operation. Through this research, methodological foundations have been formulated and adapted for the use of the mathematical modeling of the transient modes of locomotive diesel engines to optimize freight transportation, resulting in an expected decrease of 10–15% in fuel consumption. [ABSTRACT FROM AUTHOR]

Breakdown of rolling stock axle-boxes if not detected in due time may cause a rail accident or disaster. At present, a lot of advanced technologies, modern equipment and devices, which “recognizes” faulty axle-boxes when the train is in motion, have been implemented. However, the timely identification of breakdown of rolling stock axle-boxes still is an acute problem, the initial stage of damage emergence being especially problematic. Presently, rolling stock axle-box breakdown is determined according to the higher than permissible temperature of the axle-box body. The article provides statistical data of dangerously heated axle-boxes, determined train delay durations, the number of delayed trains by danger level, and dependence of damage on the season. After systematization of data on axle-box damage and heating temperatures of broken axle-boxes, heating tendencies of axle-boxes of freight wagons are described. Finally, basic conclusions are given. [ABSTRACT FROM AUTHOR]

Historically, passenger transportation by railway plays a significant role in national economies; therefore, the development of railway transport is always aimed at high-quality assurance of public transport operations. Passenger railway transportation, especially by local, suburban routes, is traditionally viewed not only as a business function, but also as a social government-supported one. For this reason, improvement of the management of expenses and incomes received from passenger transportation by railway aimed at passenger transportation efficiency as well as integration in international transport system is a matter of particular importance. The value of the run time and costs is considered as one of the most important indicators of the economic and social efficiency of passenger transport. To evaluate and optimize this value, the article proposes a mathematical model of costs incurred by a passenger and carrier for one train run, which evaluates the train length, traction and other components depending on the change in the number of passengers on the route. Studies show that in this way, it is possible to reduce passenger losses at separate Lithuanian railway routes by 4 times and to obtain a positive result at passengeroccupied routes. Having performed analysis and established trends of their changes and needs for transport vehicles, it is expedient to supplement the fleet of rolling stock with quickly and easily transformable passenger vehicles, e.g., with comfortable modular trains. It is especially appropriate when the number of passengers is low and transportation distances are not long. Membership in the European Union obligates the member states to adjust to the technical specifications for interoperability of trans-European railway corridors. The main aspect in establishing the scope and moment for introducing technical interoperability in the railway network is to determine the costs and benefit of such changes with regard to the solutions of all the concerned parties of the railway transport system. The article analyses the dependency between the expenses incurred by participants of the passenger transportation process and passenger comfort level. An integrated system of statistical indicators and a methodology that allows providing a vibration comfort evaluation in different train seats/births and levels and preparing proposals for improvement of passenger comfort and optimization of costs of participants of the passenger transportation process are selected. The improvement of passenger railway transportation process is associated with the implementation of a passenger service quality corporate management system. Its purpose is to establish and implement a customer-oriented and effective passenger service technology. Passenger transport expansion should be well-balanced with regard to the economic efficiency, environmental rationality, and social reasonability of this process. [ABSTRACT FROM AUTHOR]

Optimum haul times of running for a train schedule and mode diagrams corresponding thereto calculated using the program system passed operational check with the purpose to obtain reliable statistical estimation of their impact on reduction of the fuel consumption on haulage of trains and level of longitudinal dynamic efforts. The optimal speed of the train is chosen (defined) taking into account the given travel time and the longitudinal track profile, when the Diesel locomotive fuel consumption are minimum. Results of experimental research with long trains, weight up to 8000 tons, are presented herein. Experimental operational trips confirmed the correctness of theoretical preconditions and techniques of selection of optimum modes of driving of long trains, demonstrated potential for decrease of level of longitudinal dynamic efforts by 1.5-2 times and achievement of fuel economy on haulage up to 5-8 % when such trains move on a site with the undulating way profile. [ABSTRACT FROM AUTHOR]

The article discripes an influence of railway transport in to the economic and social live. The main advantages of railway transport in the frame of evironmentally friendly transport mode concept are presented and because of that, added value achieved. Also available disadvantages of railway transport discribing existinting bottlenacks in there, searching for the solutions thanks to implementation of internalisation processes. Taking in to account the impact of internalisation policy there are succesful observations towards improvement of fair competition between different transport modes. [ABSTRACT FROM AUTHOR]

A mathematical model to select the best rolling stocks of trains is introduced. The parameters of income and cost of the passenger transportation by railways depending on the technical characteristic of used vehicles are thoroughly evaluated. The options how to reduce the cost calculated by a model in one of the specific routes of Lithuanian Railways are given and practical decisions are argumentatively given. [ABSTRACT FROM AUTHOR]

To carry passengers, diesel and electrical trains, railcars, passenger carriages and hauled locomotives are used in AB 'Lietuvos geležinkeliai' (Lithuanian Railways). In certain sections, the number of passengers is very low (e.g. several or up to twenty passengers per 24 hours), and therefore rolling stock is used inefficiently. For this reason, it is necessary to optimize the choice of vehicles on different routes taking into account the possibilities of their application and fluctuations in the number of passengers. To this end, a mathematical model has to be developed which would allow selecting an efficient means for carrying passengers in each case and, if required, to choose rational routes by applying the above introduced model. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The publication reflects the research results of the rationalization of the rolling stock use of JSC LG Lithuanian railways to increase the reliability indicators of the freight diesel locomotive exploitation reliability. The comparative evaluation of the exploited freight diesel locomotive work duration, according to the technical documentation, by using comparative test results and indirect diesel reliability criteria approved in practice. An algorithm of work duration forecasting methodology has been created, as well as a programme complex of mathematic modelling. The differences of the results indicated in the experiment and modelled by computer do not exceed 5 ÷ 7%. The proposed and described methodology of the diesel locomotive exploitation load cycle dynamic indicator reduction, by the use of which the following is achieved: increase of the diesel work duration by 7÷10%, reduction of fuel consumption up to 10%, reduction of the load cycle dynamic indicators (increasing the fatigue stress of parts and units of the diesel) by 15÷20%. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the verticalKvdand horizontalKhddynamic coefficients as well as the stability coefficientKs, 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. [ABSTRACT FROM PUBLISHER]

The article examines curves controlling asynchronous traction motors increasingly used in locomotive electric drives the main task of which is to create a tractiveeff ort-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 eff ortspeed 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 drive using ATM (asynchronous traction motor) that gains special popularity in traction rolling stock replacing DC traction motors having low reliability. The frequency modes of asynchronous motor speed regulation are examined. To control ATM, the authors suggest the method of vector control presenting the structural schemes of a locomotive with ATM and control algorithm. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]