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1

Analysis of High Frequency Vibration of Tram Resilient Wheel

Melnik R., Sowinski B.

Machine Dynamics Research

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2018

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Vol. 42, No. 3

67--79

2

Out-of-round tram wheels – current state and measurements

Staśkiewicz T., Firlik B.

Archives of Transport

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2018

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Vol. 45, iss. 1

93--103

EN

Railway or tram wheel is never perfectly round and its surface is not ideally smooth, even at the very moment after manufacturing. This induces dynamic interaction between wheel and rail while rolling, which may result in accelerated wear, fatigue cracking, corrugation formation (both on wheels and rails) and intensified vibroacoustic emission. This paper is an attempt of summarising the current scientific achievements concerning out-of-round (OOR) tram wheels. The gathered research may provide an introduction to the broader analysis of this issue in tram technology. However there is still very little scientific works dedicated directly to light rail vehicles such as trams. The measuring methodology of out-of-round tram wheels is also described in this article. Appropriate measurements were made on the wheels of selected vehicles operated by municipal tram company in Poznań. The obtained results allowed to learn the characteristic forms of out-of-round tram wheels, among which, several forms of polygonization (ovalization, triangularization, etc.) were observed. Therefore we confirmed the thesis, that the method of fixing tram wheel rims in the lathe has a significant effect on formation of the unevenness of its rolling surface, both when new (just after turning) and, after some mileage of use, when even small irregularities become amplified. We observed also that the amplitude values from 5th up to 10th harmonic orders were increased during the operation. The initial out-of-round shape of the wheel should be likely present on the worn wheel, but with increased amplitudes of irregularities. Wheel out-of-roundness should be identified and removed at the soonest possible state to prevent its development and generating issues in the future operation, that are for example: rolling stock and infrastructure damage, impaired comfort of passengers and city inhabitants. It makes out-of-round wheels a serious problem to cope with for the vehicle operators, which can lead even to a catastrophe.

3

Surface morphology of wheels in rail vehicles in urban transport

Paczkowska M., Wojciechowski Ł., Piasecki A.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 83, nr 1

12--20

EN

Purpose: The general purpose of presented research was evaluation of surface morphology of chosen tram wheels: LUCCHINI (of Siemens Combino tram), PST (of Moderus Beta tram), and GT no 1 (of Duewag tram) operating in Poznan agglomeration. Design/methodology/approach: 3D surface profile study, macro and microscopic research with light and scanning electron microscopes, and Vickers hardness measurements were done. Findings: Wear effects were observed on the rolling surface, as well on the surface of the top of the wheel flange. Rolling contact fatigue was dominant type of wear. Abrasion was also noticed, especially on the top of the wheel flange. Changes in the surface layer were also noticed, like sever plastic deformation as: overhangs, flattened grains and delamination. Plastic deformation was the reason of hardness increase. Though the rolling surface is the surface responsible for the load transfer, more plastically deformed was the surface layer of the top of the wheel flange. Although investigated wheels was operated in different trams wear effects were similar. Research limitations/implications: The research represents part of a project considering identification of phenomena occurring in the contact zone between tram wheel and the rail funded by the National Centre for Research and Development of the LIDER program. Further research should concentrate on designing of the new wheel (new profile and modified material). Practical implications: On the base of performed research it also was possible to determine some suggestions in the order to extend tram wheel life. Originality/value: The surface morphology of tram wheels has been describe quantitatively on the base of 3D roughness parameters. Main type of wear that dominate in case of chosen tram wheels in Poznan agglomeration was identified. Main material changes in the surface layer were described in those wheels.

4

Influence of operation on tram wheels and rails surface layer condition

Paczkowska M., Wojciechowski Ł., Firlik B., Kinal G., Rewolińska A.

Inżynieria Materiałowa

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2017

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Vol. 38, nr 4

189--197

EN

Trams have become a constant in the landscape of many European metropolises in recent decades. The aim of presented research was to evaluate material changes in the surface layer of Siemens Combino, Konstal 105Na, Moderus Beta and Duewag GT tram wheels and rails as a consequence of wheel and rail exploitation in Poznan agglomeration. Microscopic study and hardness measurement were performed. The surface layer of tram wheel was highly deformed, particularly on the top of the wheel flange and under the rolling surface. In the tram wheel so-called overhangs on the top of the wheel flange and on the outer part of the rolling surface were found. Plastic deformation caused an increase of hardness in comparison to the core material. Hardness increase in case of the top of the wheel flange (even 60%) was bigger than in case of the rolling surface (up to 30%). It was also found that the longer approximate total mileage of the wheel was, the higher hardness increase of the surface layer was. ‘White layer’ as a result of presence of higher temperature during exploitation caused by friction was observed. Hard (even 2.5-times harder than the core material) and brittle layer can cause cracks. In case of Moderus Beta and Konstal 105Na wheels in the part from their frontal side decarbonization was noticed. It was stated that decarbonization is also present in the new wheel. It means that it is a defect of PST type wheel production. An area with so low hardness (below 100 HV0.1) could cause faster deformation and wear of whole wheel. A deformation in the surface layer were also revealed in rails. It was observed even in the coating area generated by welding — slip lines in austenite and martensite phase presence. Some recommendations for better wheel exploitation for Poznan Public Transport Company were also determined.

PL

Celem badań było określenie zmian, jakie zaszły w warstwie wierzchniej wybranych kół tramwajowych oraz szyn aglomeracji poznańskiej wynikające z ich eksploatacji. Lepsze zrozumienie zjawisk zachodzących na styku koła z szyną powinno przyczynić się do zwiększenia bezpieczeństwa transportu tramwajowego, a także do zmniejszenia kosztów obsługi.

5

Proposal to modify the wheel profile of Poznan Fast Tram

Finke S., Piechowiak T., Bryk K., Sienicki A.

Pojazdy Szynowe

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2016

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Nr 4

46--54

EN

PFT tram wheel profile is considered the standard profile in Poland. Despite its modern design this profile, in combination with the most commonly used rail profiles in Poland it may lead to instability, even at regular operating speeds. Although the relationship between Y/Q forces is not at a dangerous level in these cases, it leads to the increase in wheels and rails wear and the deterioration of the tram operating properties. The influence of selected, possibly small PFT profile modifications, was analyzed. These modifications were made to increase the stability on a variety of rails, an analysis of these modifications on the hypothetical process of wear of wheel/rail parts was also performed.

PL

Profil koła tramwajowego typu PST jest profilem objętym normą obowiązującą w Polsce. Pomimo nowoczesności tego profilu, w skojarzeniu ze stosownymi często w Polsce profilami szyn może on wykazywać niestabilność nawet przy eksploatacyjnych prędkościach jazdy. Pomimo, że nie występuje w tych przypadkach niebezpieczny poziom stosunku sił Y/Q, to wpływa to na zwiększenie zużycia kół i szyn oraz na pogorszenie właściwości biegowych tramwajów. Zanalizowano wpływ wybranych, możliwie małych modyfikacji profilu PST, dokonanych w celu zwiększenia stabilności na różnych szynach, dokonano również analizy tych modyfikacji na hipotetyczny proces zużywania elementów koło-szyna.

6

Analysis of high frequency vibration of tram monobloc wheel

Sowiński B.

Archives of Transport

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2016

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Vol. 39, iss. 3

65--75

EN

European Environmental Agency estimates that about 120 million people in the EU (over 30% of the total population) are exposed to traffic noise above 55 Ldn dB. It is estimated that 10% of the EU population is exposed to noise associated with the rail traffic. The two main sources of traffic noise comes from vehicles engines and the noise generated in the contact between the wheel and the road. In the latter the considerable part the noise is due to phenomena occurring in a wheel tram – rail system. Therefore, the problem of reducing the noise generated by railway vehicles is the subject of many studies, both experimental and theoretical. Commonly used wheel trams so called "resilient wheels" are equipped with layer made of a resilient material, e.g. rubber, between the tread and the wheel disc. But the monobloc tram wheel is the standard design against which should be carried out the studies on reduction of noise in wheel-rail system. This paper presents the results of calculations related to eigenforms, eigenfrequencies and Frequency Response Function of a three-dimensional model of a monobloc tram wheel. The calculations were carried out using the finite element method. Vibration analysis was performed for the range to 5 kHz. Analysis carried out has shown that the wheel tread plays a more important role in the generation of high-frequency vibrations.

7

Analiza efektów zużywania się wybranych obręczy kół tramwajowych w aglomeracji poznańskiej

Paczkowska M., Wojciechowski Ł., Kinal G., Ostrowska K., Okoniewicz P.

Inżynieria Materiałowa

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2015

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Vol. 36, nr 6

391--395

PL

Celem badań było określenie dominujących typów uszkodzeń obręczy wybranego pojazdu szynowego, a także zmian materiałowych będących wynikiem zużycia obręczy koła i szyny. Powierzchnie obręczy poddano badaniom makroskopowym i profilografometrycznym, twardości sposobem Vickersa oraz mikroskopowym za pomocą mikroskopu świetlnego Zeiss Epiquant sprzężonego z kamerą CCD i skaningowego mikroskopu elektronowego Tescan Vega 5135 wraz z mikroanalizatorem rentgenowskim PGT Avalon. Sprawdzony również został skład chemiczny materiału obręczy za pomocą spektrometru jarzeniowego GDS 500A firmy LECO. Podstawową formą zużycia badanych obręczy kół, jakie zostało rozpoznane na podstawie badań makroskopowych, był shelling. Najwięcej efektów zużycia zaobserwowano na powierzchniach tocznych. Należy zaznaczyć, że rozwój shellingu był w początkowej fazie. Powstałe wykruszenia nie występowały na całym obwodzie, a ich wielkość była nieduża. Wynika to prawdopodobnie z tego, że tramwaje eksploatuje się na krótkich odcinkach w porównaniu z pociągami. Ponadto w niewielkich obszarach warstwy wierzchniej stwierdzono obecność tzw. białej warstwy, co pozwala przypuszczać, że lokalnie dochodziło do większego (niż dla shellingu) nagrzewania ślizgających się powierzchni tocznych kół. Był to jednak proces lokalny, niemający kluczowego znaczenia w ogólnym przebiegu zużywania. Obręcze kół ulegały silnemu odkształceniu plastycznemu w szczególności na wierzchołkach obrzeża i przy skosach zewnętrznych profilu tocznego. Silne zgnioty spowodowały zwiększenie twardości o blisko 70% w porównaniu z twardością materiału wyjściowego. W warstwie wierzchniej rozpoznano MnS. Wtrącenia te, występujące np. w mikrostrukturze wierzchołków obrzeży, inicjowały delaminację. Może to przyczyniać się do powstawania pęknięć i w rezultacie do zwiększonego zużywania obręczy.

EN

The aim of presented research was evaluation of the main types of tram wheel wear of chosen rail vehicle and material changes which appear as a consequence of wheel and rail wear. Following tests was performed: macroscopic research, profile tests, Vickers hardness measurements, microscopic research with light microscope (Zeiss Epiquant with CCD), scanning electron microscope (Tescan Vega 5135) with X-ray microanalizer (PGT Avalon). The chemical composition was also checked with fluorescent spectrometer (LECO GDS 500A). The basic form of wear was shelling, which was detected by macroscopic research. The most damage surface was rolling surface. It has to be underline that the shelling was in early stage of growth. Created shells did not appear in the whole circumference of wheel and their size were relatively not huge. It is probably due to short distances characteristic for trams (in the comparison with trains). Moreover, in same regions of rolling surface, so called white layer was detected. It allows to state that sliding surfaces of wheel were (in a very small areas) heated in to higher temperature than it happens in case of shelling. Nonetheless, it was very local process, so it is rather not important in general wear of tested wheels. Tram wheels were highly deformed, particularly on the top of the edge of the wheel, and in the vicinity of outside angle of rolling profile. High deformation caused 70% hardness increase in comparison to the core material. In microstructure MnS was detected. Its presence in the surface layer of the top of the edge of the wheel caused delamination. It could help to crack initiation and, as a result, more intensive wear of tram wheels.