Electrodynamic braking in high-speed rail transport

The paper considers electrodynamic braking of trains, which is of particular importance for high-speed railway transport from theoretical and technical perspectives. Braking methods used for high-speed trains should ensure compatibility and redundancy of braking systems. They include a mechanical method (based on adding frictional disks to wheelsets), as well as magnetic braking, which is being currently implemented and based on eddy currents, etc. High-speed trains have AC/DC engines, for which the principles of electric braking can be applied. Electrodynamic braking is of particular importance for high-speed transport using linear motors and developing the speed of 400–500 km/h. These traction rolling stocks will not have commonly used trucks. The tests in this area are being conducted in Japan and Germany now. The paper suggests some theoretical and practical solutions to these problems. Schematic diagrams of the locomotive braking and ways of controlling the braking force by varying electric circuit parameters are presented. The authors suggested contact-free regulation of braking rheostat resistor for controlling braking force in rheostatic braking. A schematic diagram of harmonizing electrified railways and power system’s upgrading aimed at ensuring power regeneration is also presented

ALGORITHM FOR CHOOSING TRACTION ROLLING-STOCK FOR RAILWAY LINE RAIL BALTICA / PREKINIŲ ŠILUMVEŽIŲ MAGISTRALEI „RAIL BALTICA“ PARINKIMO ALGORITMAS

The article analyses traction rolling-stock for freight transportation presently used by AB Lietuvos geležinkeliai. The paper explores and compares technical data on the above mentioned rolling-stock and estimates exploitation expenses. Following an assessment of forecasting freight flows on the future railway line Rail Baltica, an algorithm for selecting traction rolling-stock is proposed. The efficiency of locomotives operating on the railway is determined taking into account three multi-criteria evaluation methods: the sum of ratings, simple additive weighting and geometric mean method. Locomotives are estimated in accordance with technical, economic and ecological aspects. The results of possible performance efficiency of rolling stock have been determined changing weight coefficient values of the criteria. Santrauka Straipsnyje nagrinėjami šiuo metu AB ,,Lietuvos geležinkeliai“ kroviniams vežti naudojami traukos riedmenys: analizuojami ir lyginami techniniai duomenys, vertinamos eksploatavimo sąnaudos. Įvertinus krovinių srautų prognozes tiesiamoje ,,Rail Baltica“ geležinkelio magistralėje, pasiūlytas traukos riedmenų kroviniams vežti parinkimo algoritmas. Šilumvežių šioje magistralėje naudojimo efektyvumas nustatomas trimis daugiakriterio įvertinimo metodais: vietų sumos metodu, rodiklių įverčio metodu ir geometrinio vidurkio metodu. Šilumvežiai vertinami techniniais, ekonominiais ir ekologiniais aspektais. Keičiant kriterijų svarbos koeficientų reikšmes, nustatyti skirtingi riedmenų panaudojimo efektyvumo rezultatai. Raktiniai žodžiai: geležinkelio traukos riedmenys; magistralė ;;Rail Baltica“; eksploatacinės sąnaudos; daugiakriterio vertinimo metodai; eksploatavimo efektyvuma

Electric drives of traction rolling stocks with ac motors

The paper considers the variation of circuit design of the electric drives in traction rolling stocks when traditional DC electric machines are replaced with AC electric machines. Simplified circuit diagrams of the electric drives using electric machines of non-commutator type are offered. Operational defects of DC traction engines are weighed against some positive characteristics of direct current series excitation in traction engines, determining their extensive use in the electric drives of traction rolling stocks. However, the rapid development of semiconductor devices, e.g. thyristors and IGBT transistors, led to the creation of a great variety of semiconductor inverters. This made it possible to develop an autonomous three-phase power supply system for diesel locomotives and algorithms for the AC traction motors and to obtain engine characteristics matching the tractive force by using voltage frequency and current inverters. A mathematical justification of the engine torque and tractive force control as well as its particular characteristics is provided. The graphs demonstrating the particular ways of changing the electrical parameters of an asynchronous motor with a squirrel-cage rotor are also presented

New Locomotive Energy Management Systems

Economic indicators of electrodynamic braking have not been properly estimated. Vehicles with alternative power trains are transitional stage between development of pollution - free vehicles. According to these aspects the investigation on conventional hybrids drives and their control system is carried out in the article. The equation that allow evaluating effectiveness of regenerative braking for different variants of hybrid drive are given. Presenting different type locomotive energy savings power systems, which are using regenerative braking energy any form of hybrid traction vehicles systems, circuit diagrams, electrical parameters curves.W artykule zostały przeanalizowane nowe możliwości oszczędzania energii lokomotyw. Autor rozpatruje możliwości rekuperacji energii pociągów z napędem elektrycznym do sieci kontaktowej przy dużych szybkościach i gromadzenia energii przy małych szybkościach. Przedstawione są propozycje wariantów struktury lokomotyw hybrydowych z zastosowaniem tendera, w którym znajdują się baterie. Zgromadzona w tych bateriach energia może być w dalszym ciągu wykorzystana do trakcji, oświetlenia, klimatyzacji, itd. Przedstawiono schematy, diagramy, wykresy charakteryzujące możliwości rekuperacyjnego hamowania

The influence of railroad curves on the wear of lubricated and unlubricated wheel flanges

W artykule omówiono konieczność wyznaczania stanu lokomotywowych zestawów kołowych i jego zmian. Przedmiotem badań jest obrzeże koła lokomotywy. Bezpieczny ruch kolejowy w dużej mierze zależy od niezawodności zestawu kołowego lokomotywy. W przedstawionej pracy skonstruowano złożony model ścierania obrzeża koła lokomotywy dla niesmarowanych i smarowanych obrzeży kół. Model ten uwzględnia przebieg lokomotywy i promień krzywizny.Therefore, the condition of the locomotive wheelsets and its variations should be determined. Research object is the locomotive wheel flange. Safe railway traffic largely depends on the locomotive wheelset reliability. A complex model of the locomotive wheel flange abrasion, taking into account the locomotive run and curve radius, was constructed for unlubricated and lubricated wheel flanges

Porównanie wydajności lokomotyw spalinowych przeznaczonych do przewozu pasażerów

Railway transport usually employed for passenger transportation embraces passenger locomotives, diesel trainsets and electric trains as well as railcars, diesel or electric trains are mostly used on suburban routes, while passenger or electric locomotives haul the carriages on interurban routes

A change of complex economic indicators of passenger rolling stock deterioration

Szereg kryteriów opisujących stan lokomotywy z różnych perspektyw może być używanych do oszacowania ich stanu. Kilka złożonych albo zintegrowanych kryteriów obrazujących stan ogólny lokomotyw Diesla może też być alternatywnie używanych w takim przypadku. Zintegrowany wskaźnik wyników charakteryzujący stan lokomotyw może być wyrażony przez opisane funkcjonalne zależności. Analiza dostępnych metod dla złożonej oceny stanu taboru kolejowego pokazała, że wydajność całkowita lokomotywy może być opisana przez bezwymiarowy wskaźnik.Various criteria describing the state of a locomotive from various perspectives can be used to assess its performance. Some complex or integrated criteria reflecting a general state of Diesel locomotives can also be used. an integrated performance indicator characterizing the locomotive performance is expressed by the following functional relationship. 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

Making up and renovation of trains

Major constituent parts of the railway system are rolling stock and various objects making its infrastructure. Their maintenance is rather expensive, while renovation requires large investments. The researchers all over the world are working hard to make these investments effective. To make a decision in economics its economic effect should be established first. Generally, the latter is expressed as the repay time of investment or the economic effect in the particular period of time specified according to the particular technical requirements. The repay time is usually calculated optimizing the choice of the particular elements (i.e. an engine, gear-box, transmission, etc.) of the train. The optimization of the selection of the trains would require a comparative analysis of economic effects (expressed in monetary units at the particular time interval) of the alternative solutions available. If the target objects of the investments are well - known, the first approach described in the present paper may be used to determine the repay time of investment thus enabling us to check the effectiveness of a potential investment. If an object for the potential investment should be determined, implying that its major characteristics should be described, the second method based on increasing the economic effect may be applied

The economic effect of using biological diesel oil on railway transport

The tests performed by the authors have shown that diesel locomotive engines efficiently operate using a mixture of diesel oil and about 40% of rapeseed oil methyl ester (RME) while their ecological and economical parameters do not differ much from those of the locomotives operating on pure diesel oil. When biodiesel is used, the pollutants released into the atmosphere by an engine are less harmful. Therefore, the respective laws of the Republic of Lithuania provide for some financial incentives and allowances to transport enterprises using biological diesel oil. The paper presents a mathematical model for determining the expenses associated with the use of biological diesel oil

Статистические методы изучения износа колесных пар

Wheels of locomotive axes are subject to wear during operation, when the wheel is contacting the track in the railway curves both with its rolling surface and flange. The quality of both of the mentioned surfaces has a direct impact on railway traffic safety; therefore, their wear is under special control. Statistic methods of research of wear of locomotive axes can be efficiently divided into two types: regression and probability. The article discusses the examples of research completed in Lithuanian railways. Recommendations on which method is the most appropriate method to use in which situation is provided according to results of the research.При прохождении локомотивом кривых, колеса колесных пар подвержены износу в момент соприкосновения поверхности качения и гребня с рельсами. Качество обеих упомянутых поверхностей оказывает непосредственное влияние на безопасность движения; по этой причине их износ требует особого контроля. Статистические методы изучения износа колесных пар можно разделить на два типа: регрессионные и вероятностные. В статье обсуждаются исследования, проведенные Литовскими железными дорогами. По результатам этих исследований даются рекомендации по выбору подходящего в той или иной ситуации метода