This paper contains a comparison of air pollutant emissions of different vehicle types and a presentation of the issue of assessing the environmental impact of hybrid, conventional, and electric vehicles in terms of the changing electricity production sources in Poland over time. The research method used in this paper for hybrid and conventional vehicles was on-road testing of air pollutant emissions using the SEMTECH DS analyzer. Air pollutant emissions from electric vehicles were determined based on the authors’ analytical method involving air pollutant emission factors published annually in Poland by the National Centre for Emissions Management (KOBiZE). Measurements of on-road air pollutant emissions for hybrid and conventional vehicles were compared with electric vehicle emissions; however, the electric vehicle emissions covered the area of electricity production. The hybrid vehicle emissions recorded in on-road tests have been corrected for the emissions that arise from the production of the electricity consumed by the hybrid vehicle. The recovery phenomenon was not analyzed. The aim of this paper is to compare air pollutant emissions of electric vehicles with those of hybrid and conventional vehicles, considering the energy transition that has taken place in Poland in the last decade.

This paper presents investigations of rail vehicle bogies of the Y25 type. The Y25 bogie family is one of the most commonly used freight car bogie designs. In addition to several significant advantages characterising this design, several disadvantages have also been observed since the beginning of more than fifty years of its operation in several types of cargo vehicles. One of these defects observed in real systems is its “unsatisfactory running stability”, particularly for long straight tracks. This paper used the commercial engineering software VI-Rail (2010.13.0) to create a model of a gondola car (type 412W Eaos) with two Y25 bogies. The car model was tested in empty and loaded (maximum permissible load) modes. Its motion along straight and curved tracks with different radii values was analysed. The vehicle velocity was changed from a few m/s to the maximum values for which stable solutions of the model existed. For each route, the nonlinear critical velocity was determined, defining the maximum operating velocity of the modelled car. The model solutions were recorded, while just one was selected to present the results—the first wheelset’s lateral displacement ylw. Conjecture about its “imperfect running quality” on curved tracks was confirmed. The possible appearance of self-exciting wheelset vibrations in the modelled car’s operating velocity range in a laden state was also observed. The research results on the impact of changes in the bogie suspension parameters on the vehicle model’s stability are presented. The crucial parameter in the bogie suspension was indicated. Reducing its value by several percent about the nominal value increases the critical velocity of the car to values higher than the maximum operating velocity of the modelled vehicle.

The article presents investigations of rail vehicle bogie of Y25 type. The Y25 bogie family is one of the most commonly used freight car bogie designs. In addition to several significant advantages characterising this design, it also has several disadvantages observed since the beginning of more than fifty years of operation in several types of cargo vehicles. One of these defects observed in real systems is "unsatisfactory running stability", particularly at long straight tracks. The article used commercial engineering software VI-Rail to create a model of the gondola car (type 412W Eaos) with two Y25 bogies. The car model was tested empty and loaded (maximum permissible load). Motion along straight and curved tracks with different radii values was analysed. The vehicle velocity was changed from a few m/s to the maximum values for which stable solutions of the model existed. For each route, a non-linear critical velocity was determined, defining the maximum operating velocity of the modelled car. The model solutions were recorded, while just one was selected to present the results - the first wheelset lateral displacement ylw. The opinion about the "imperfect running quality" in curved tracks was confirmed. The possible appearance of self-exciting wheelset vibrations in the modelled car's operating velocity range in the laden state was also observed. The research results on the impact of the bogie suspension parameters change on the vehicle model stability are presented. The crucial parameter in the bogie suspension was indicated. Reducing its value by several percent about the nominal value increases the critical velocity of the car to values higher than the maximum operating velocity of the modelled vehicle.

Y25 (25Tn) bogies have been used in freight cars for over 50 years. It is a proven design with a positive opinion in many European countries. In addition to the generally positive opinion about the operational properties of the Y25 bogies, there are sometimes publications whose authors notice certain imperfections related mainly to the so-called running instability, resulting in derailment under certain motion conditions. This paper presents results simulation of motion tests of a freight car with Y25 bogies. A freight car model was created using the VI-Rail software. The research focus on determining the critical velocity and examining nature of the model solutions in the overcritical velocity range. Straight track sa well as curved track motion is analysed. Empty and full wagon properties are considerd. Impact of changes the suspension system selected parameters values on vehicle model solutions stability as well as the vehicl impact on track was analysed.

The simulation tests results of the rail vehicle - track system model are presented in this article. The purpose of the research was to determine the influence of chosen vehicle suspension element parameters on stability and safety of motion. Simulation model of 4-axle passengers coach was created with use the VI-Rail software. Damping component of the second stage elastic-damping element in the longitudinal direction was selected. For two values of the damping parameter applied, such a few system parameters were determined: critical velocity, values of solutions in a wide velocity range, lateral wheelset-track forces and values of safety factor against derailment. The vehicle motion was simulated along a straight track and curved track with a radius of R = 3000, 4000 and 6000m. Comparison of vehicle model features for particular damping component values were done. The results are presented in the form of diagrams illustrating changes in the tested system parameters as a function of vehicle velocity.

The properties of a classic railway track largely depend on the properties of the sub-grade, which is most often a natural creation. Atmospheric phenomena (e.g. temperature changes, heavy rainfall) can locally reduce the elasticity of the subgrade and create conditions conducive to permanent track deformation. One of the most common forms of a track fragment destruction is the loss of foundation support (one or several neighbouring sleepers) resulting from the indentation of the ballast material in the subgrade. The pressure of a vehicle passing through a damaged section of the track causes the so-called dynamic track irregularity. The impact of dynamic track vertical irregularity on the values of wheel-rail contact forces of a passing vehicle was investigated. The model of the passenger wagon-track system was created using the VI-Rail tool. The vehicle motion on curves with different values of track radius and superelevations was investigated. Vertical track irregularities occur on the internal rail only. The lengths of the track irregularity correspond to one, two or three sleepers unsupported on one side. The test results are presented in the form of diagrams and referred to applicable standards and regulations.

The article presents authors’ recent results on nonlinear lateral stability of rail vehicles in a curved track. The theories of self-exciting vibrations and bifurcation are the key elements here. The general objective is presentation of extended use of the earlier worked out authors’ method to more complex rail vehicle models. Two 4-axle vehicle models were created. The first one represents coach MKIII described with multibody software by the first author. The second one represents coach 127A described with use of engineering multibody software VI-Rail. The models are described, and method of the analysis is shortly reminded. Then, results for both models are presented. They include verification of the limit cycle possible passage from straight track to circular curve and stability maps for regular curves of different radii and straight track. Next influence of selected suspension parameter and wheel–rail coefficient of friction on vehicle stability is shown. The more general objective is the authors’ say in the hot polemics on the advisability of rail vehicle stability analysis in curves and on the advantages of the nonlinear methods of such analysis over the linear ones.

Right estimating of the coefficient of friction between the wheel and rail is essential in modelling rail vehicle dynamics. Constant...

Analysis of lateral stability of rail vehicle model is the subject of present paper. The method used by the author is based on bifurcation diagrams creation and analysis. The continued study of stability of vehicle model in straight track and curved track and form of the results presentation are original features of the method. Results for the straight track and wide range of radii of the curved track are presented jointly on the combined bifurcation diagrams in this paper. Multibody dynamics software VI-Rail was used for numerical analysis. Passenger vehicle model and track models were created. Analysis of track gauge influence on vehicle model stability is main aim of this paper. But analysis of possibility to adopt the method worked out earlier to the newly used numerical code and model of 4-axle vehicle is the aim either.

Stateczność ruchu pojazdu szynowego na torze zakrzywionym – to ogólne zagadnienie badawcze, które stanowi przedmiot wieloletnich badań autorów [6– 12] i którego fragment zawiera niniejszy artykuł. Podstawowym parametrem używanym w analizie stateczności ruchu jest prędkość krytyczna. W dotychczasowych badaniach autorzy wyznaczali prędkość krytyczną w sposób przybliżony. Pozwalało to na ograniczenie ilości badań symulacyjnych i skrócenie czasu ich realizacji. Istotą badań, których wyniki zamieszczono w artykule, jest precyzyjne wyznaczenie wartości prędkości krytycznej i porównanie nowych wartości z wcześniej wyznaczonymi w sposób przybliżony. Parametrem, który jest przedmiotem zainteresowania w badaniach są przemieszczenia poprzeczne zestawów kołowych.