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In recent years, the number of long-distance trains running on non-electrified lines has been increasing in Poland. Unfortunately, trains running on non-electrified lines, unlike those running on the hook of electric locomotives, are very often canceled, especially in the winter. In this research, the analysis of which lines had the most frequent cancellations of trains in 2021 and the reasons for these cancellations were analyzed. The results show that the most common cause of train cancellations was the lack of an efficient locomotive at the starting station. Most often, accessibility problems concern Czech series 754 diesel locomotives. The numbers of canceled trains in February 2021 and 2022 were also compared. The comparison showed that although the situation is far from ideal, it has improved significantly. [ABSTRACT FROM AUTHOR]

The article investigates the influence of preventive maintenance on the reliability and availability indexes of the railway means of transport, which also determine the economic aspects of their operation and maintenance. The research was done using the method based on fault tree analysis (FTA) and Monte Carlo simulation. The authors performed a cause and effect analysis of the occurrence of undesirable events during the operation of selected vehicles. They identified the weakest components of the rail vehicle that affect the downtime and mean availability most significantly. Specialized software including Weibull++, BlockSim, and MiniTab aided calculations were used to illustrate the application of the results of a modernization project involving a 6Dg diesel locomotive, carried out in cooperation with the biggest Polish rail carrier. The applicability of the proposed tools has been verified on the example of a selected sample of 75 diesel locomotives employing data on their use and maintenance acquired in the real operation process. The obtained results indicate that the proposed approach can be particularly useful in practice when assessing the applied rail vehicle maintenance strategy, and while developing new strategies and selecting the best one to implement. [ABSTRACT FROM AUTHOR]

This paper considers the braking process of a mine diesel locomotive with hydrostatic mechanical transmission (HSMT) operating according to the "input differential" scheme. Braking process modeling involves four implementation methods. Identification and systematization of basic regularities in the distribution of power flows within a closed transmission contour in the process of braking have been performed with the help of software support developed by means of MatLab/Simulink. The simulation results of braking due to the hydrostatic transmission and the braking system during the movement of a diesel locomotive in the transport and traction ranges are presented in the form of graphical correlations. The process of theoretical studies of the braking process of a diesel locomotive with HSMT operating according to the "input differential" scheme has helped determine that, in terms of deceleration at the expense of a hydrostatic drive (HSD) and braking system while preserving kinematic engine-wheels connection, it is not permitted to implement this method of braking process as it is followed by excess of the allowable value of working pressure differential within HSD up to 2.8 times. [ABSTRACT FROM AUTHOR]

To analyze the braking process of a mine diesel locomotive with hydrostatic- mechanical transmission (HSMT), a mathematical model has been developed. In contrast to available models, this one takes into consideration rules of changes in controlling the parameters of hydrostatic drive (HSD) and implementation methods for the braking process. Moreover, the model makes it possible to study changes in kinematic parameters, power parameters and energy parameters of HSMT under various conditions of a mine diesel locomotive operation. It has been determined that the use of HSMT operating according to the "output differential" scheme is possible, providing kinematic disconnection of the engine from the driving wheels (for emergency braking with complete stop of the diesel locomotive) or at the expense of HSD while preserving the kinematic connection between the engine and the wheels (for deceleration). Use of the braking system together with HSD or the braking system only while preserving the kinematic connection between the engine and the wheels will result in HSMT failure. [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 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. [ABSTRACT FROM AUTHOR]