SELECTED PROBLEMS IN RAILWAY VEHICLE DYNAMICS RELATED TO RUNNING SAFETY

The paper includes a short review of selected problems in railway vehicle-track system dynamics which are related to the running safety. Different criteria used in assessment of the running safety are presented according to the standards which are in force in Europe and other countries. Investigations of relevant dynamic phenomena, including the mechanism of railway vehicle derailment, and the resulting modifications of the running safety criteria are also discussed

STATISTICAL ANALYSIS OF DYNAMICAL QUANTITIES RELATED TO RUNNING SAFETY AND RIDE COMFORT OF A RAILWAY VEHICLE

This paper investigates the variation of track geometrical parameters that lead to a local increase of specific dynamical quantities of a railway vehicle, possibly beyond their acceptable values. In particular, the changes of track geometry are investigated near track points where the running safety or ride comfort are significantly decreased during the vehicle motion due to track irregularities. The investigated dynamical quantities include the lateral and vertical forces at the wheel-rail contact as well as the acceleration of the vehicle body. The vehicle motion has been simulated using a non-linear model of a passenger car moving along a nominally tangent stiff track with random geometrical irregularities. The relationship between the local track condition and the maxima of the dynamical quantities was investigated with the statistical method proposed by the author. The performed analysis clearly identifies the characteristic variation of track irregularities that leads to a large increase of the investigated dynamical quantities at some track points

Selected problems in railway vehicle dynamics related to running safety

The paper includes a short review of selected problems in railway vehicle-track system dynamics which are related to the running safety. Different criteria used in assessment of the running safety are presented according to the standards which are in force in Europe and other countries. Investigations of relevant dynamic phenomena, including the mechanism of railway vehicle derailment, and the resulting modifications of the running safety criteria are also discussed

Running safety of a railway vehicle in the presence of random track irregularities

The paper presents the author's investigations on dynamics of a vehicle, especially the effect of various factors on the running safety. applied simulation methods used for analysis of running safety are in agreement the technical standards UIC 518 and EN 14363. The numerical simulations are performed for non-linear model of railway vehicle (a passenger car) moving along a tangent trach with lateral and vertical geometrical irregularities of random character. The obtained results are used to study how the derailment coefficient is affected by the ride velocity, the parameters of the primary and secondary vehicle suspension, the wear of wheel and rail profiles as well as the track condition. The investigation of running safety is further enhanced by performing the spectral analysis ofthe dynamical responses ofthe railway vehicle-track system. It is found that there is a direct relation between the obtained power spectral density (PSD) of the derailment coefficient and the PSD of the lateral and angular wheelset displacements showing the characteristic oscillations due to the wheelset hunting. Finally, the paper presents the results of the statistical analysis of local track geometrical irregularities occurring in the vicinity of the track points where the derailment coefflcient attains large values

Symulacyjne badania komfortu jazdy dla różnych położeń pasażera w pojeździe szynowym

The paper presents the analysis of ride comfort of a railway vehicle based on the results of numerical simulations for a model of a passenger car moving along a tangent track with random geometrie irregularities. The lateral and vertical rms accelerations in 1/3 octave frequency bands as wen as the weighted rms accelerations are calculated at several positions within the car body for two track sections with different track condition and for various vehicle velocities. The obtained accelerations are compared with the comfort and decreased fatigue boundaries according to the ISO 2631-1 and PN-91/S-04100 standards.W pracy przedstawiono analizę komfortu jazdy pasażera pojazdu szynowego na podstawie wyników symulacji numerycznych dla modelu wagonu pasażerskiego poruszającego po torze prostym i sztywnym o losowych nierównościach geometrycznych. Wyznaczono poprzeczne i pionowe przyspieszenia skuteczne w pasmach tercjowych oraz odpowiadające im przyspieszenia ważone dla różnych położeń pasażera wewnątrz nadwozia pojazdu. Badania przeprowadzono dla dwóch odcinków toru o różnym stanie utrzymania oraz dla różnych prędkości jazdy. Otrzymane przyspieszenia porównano z wartościami granicznymi określonymi w normach ISO 2631-1 i PN-91/S-04100

The use of a linear half-vehicle model for the optimization of damping in the passive suspension system of a railway car

The paper presents a methodology of optimizing the parameters of the passive suspension system of a railway vehicle. A linear half-vehicle model and an example of the procedure carried out to optimize a selected parameter of the model have been demonstrated. A method of the selection of damping in the suspension system of a railway vehicle, based on over 40-year achievements of the cited authors of publications in the field of motor vehicles, has been shown. The optimization of linear damping in the secondary suspension system of a passenger carriage moving on a track with random profile irregularities has been described in detail. The algorithms adopted for the calculations have a wider range of applicability; especially, they may be used for determining the optimum values of the other parameters of the railway vehicle model under analysis, i.e. stiffness of the secondary suspension system as well as stiffness and damping of the primary suspension system

The use of a linear half-vehicle model for the optimization of damping in the passive suspension system of a railway car

The paper presents a methodology of optimizing the parameters of the passive suspension system of a railway vehicle. A linear half-vehicle model and an example of the procedure carried out to optimize a selected parameter of the model have been demonstrated. A method of the selection of damping in the suspension system of a railway vehicle, based on over 40-year achievements of the cited authors of publications in the field of motor vehicles, has been shown. The optimization of linear damping in the secondary suspension system of a passenger carriage moving on a track with random profile irregularities has been described in detail. The algorithms adopted for the calculations have a wider range of applicability; especially, they may be used for determining the optimum values of the other parameters of the railway vehicle model under analysis, i.e. stiffness of the secondary suspension system as well as stiffness and damping of the primary suspension system

Optimization of Train Energy Cooperation Using Scheduled Service Time Reserve

The main aim of the paper was to develop an innovative approach to the preliminary estimation possibility of train energy cooperation based on data from timetables, without traction calculations. The article points out the need to strive for sustainable and environmentally friendly transport. It was pointed out that rail transport using electric traction is one of the more ecological branches of transport. It also offers a number of possibilities for improving energy efficiency and reducing energy consumption, one of which is the recovery and reuse of energy lost in the electrodynamic braking process. The main ways in which such energy can be used are listed, but the focus is mainly on the aspect of the so-called “energy cooperation” of trains. Then, the current state of the research and knowledge on the narrowed scope of rail traffic management and recuperative braking in rail transportation is presented; an innovative approach to the indirect optimization of the amount of recuperated electrical energy immediately usable by another vehicle by maximizing the duration of energy co-optimization is proposed; and the authors’ function is proposed to enable optimization, taking into account various parameters. The optimization was performed with the use of a proprietary, multi-criteria objective function and the Solver optimization module. Finally, the results obtained using the proposed approach are presented and illustrated with the example of train timetables used by some of the largest railway stations in Poland

Optymalizacja efektywności hamowania odzyskowego w transporcie szynowym przez sterowanie czasem przyjazdu na stację

Artykuł nawiązuje do poprzednich prac autorów, w których przedstawiono model organizacji ruchu kooperujących pociągów z uwzględnieniem optymalizacji wykorzystania energii zwracanej do sieci jezdnej. W przedstawionym artykule zmodyfikowano model, zmieniając główną zmienną sterującą mającą wpływ na efektywne wykorzystanie energii, z czasu odjazdu na czas przyjazdu pociągu na stację lub przystanek. Optymalizacja jest dokonywana przez sterowanie czasem przyjazdu na stację w dopuszczalnym (rozkładowym) jego zakresie i przy zachowaniu rozkładowego czasu odjazdu, z wykorzystaniem metody równego podziału (bisekcji) do osiągnięcia optymalnego rozwiązania. Zmodyfikowaną metodę optymalizacji zaimplementowano w autorskim modelu organizacji ruchu kolejowego. Uwzględniono w nim optymalne wykorzystanie energii odzyskanej podczas hamowania elektrodynamicznego, przy zastosowaniu strategii przesyłu energii do sieci jezdnej, zakładając kooperację pary pociągów, całkowitą wielkość energii możliwej do odzyskania oraz czas postoju na stacji

Optimization of Train Energy Cooperation Using Scheduled Service Time Reserve

The main aim of the paper was to develop an innovative approach to the preliminary estimation possibility of train energy cooperation based on data from timetables, without traction calculations. The article points out the need to strive for sustainable and environmentally friendly transport. It was pointed out that rail transport using electric traction is one of the more ecological branches of transport. It also offers a number of possibilities for improving energy efficiency and reducing energy consumption, one of which is the recovery and reuse of energy lost in the electrodynamic braking process. The main ways in which such energy can be used are listed, but the focus is mainly on the aspect of the so-called “energy cooperation” of trains. Then, the current state of the research and knowledge on the narrowed scope of rail traffic management and recuperative braking in rail transportation is presented; an innovative approach to the indirect optimization of the amount of recuperated electrical energy immediately usable by another vehicle by maximizing the duration of energy co-optimization is proposed; and the authors’ function is proposed to enable optimization, taking into account various parameters. The optimization was performed with the use of a proprietary, multi-criteria objective function and the Solver optimization module. Finally, the results obtained using the proposed approach are presented and illustrated with the example of train timetables used by some of the largest railway stations in Poland