Institute of Fundamental Technological Research

The aim of the article is to develop a method for the analysis of tram dynamics related to safety during operation. To achieve this, a mathematical model of the vehicle represented by a multibody simulation MBS system is used. Models of tram with a classic and innovative drive, based on a system of independently rotating wheels on crank axles are analyzed. A new configuration of an innovative drive control of the considered vehicle with the use of braking of independent wheels is proposed. A new geometry of test track is presented. During numerical investigation the values of 'Y' leading forces of tram wheels with the considered innovative drive proved to be lower than in the corresponding vehicle with standard wheelsets. It has been demonstrated that the active control systems are of key importance and should be applied in such innovative tram drives.

maintenance of safety, reliability of trams, derailment of tramcar, numerical tests, drive with independently rotating wheel

The existing European standard EN 14363 covers all necessary tests for different railway vehicles, but it is inadequate for tram vehicles, especially in safety against a derailment examination. Its operational conditions are much different. Trams overcome horizontal curves with much smaller radii than railway vehicles. There is a large diversity in wheel-rail pairing, i.e. almost every public transport operator uses a different wheel profile. In the running gear design much more rubber-metal elements are used in order to ensure a low-floor interior and to keep the kinematic envelope. Apart from standard vehicle configuration, i.e., a carbody on two bogies, in modern tram designs numerous arrangements are applied: wagons with one outer bogie, wagons with one centered bogie, wagons without bogies (sedan) etc., where twisting shims cannot be used to achieve the required twist. The described issues imply that the methodology of safety against derailment described in EN 14363 standard cannot be applied without any modifications. This paper presents a new proposal for a simulation safety against derailment for a vehicle with an arbitrary configuration of wagons and running gears. The numerical analyses have been performed by means of the Simpack Rail software

Safety against derailment, Tram vehicle Numerical, simulation Running dynamics, Simpack rail software

In the paper, simulation results of safety against derailment for a tramway vehicles with an arbitrary configuration of wagons and bogies is presented. The existing European standard EN 14363 covers all necessary tests for different railway vehicles, but it is inadequate for tramway vehicles, especially in safety against a derailment examination. Its operational conditions are much different. The described observations suggest that the methodology of safety against derailment testing described in the EN 14363 standard cannot be used without any modifications in the case of testing of tramway vehicles. On the basis of the computational results, a significant influence of different configurations of urban tramway vehicles on the wheel-rail contact forces was discussed, in particular on the Y/Q derailment factor.

tramway dynamics, safety against derailment, simpack, numerical study

Pojazdy tramwajowe charakteryzują się dużą różnorodnością w zakresie konfiguracji struktur nadwozi oraz układów biegowych. Ma to związek z ich eksploatacją w wysoko zurbanizowanych obszarach miejskich i koniecznością przystosowania do masowej obsługi podróżnych o różnych potrzebach przewozowych
(osoby o ograniczonej możliwości ruchowej, osoby na wózkach inwalidzkich, osoby z wózkami dziecięcymi). Nie bez znaczenia jest również istniejąca infrastruktura (minimalne wartości promieni łuków poziomych i pionowych, wysokości krawędzi przystankowej względem poziomu główki szyn). W stosunku do pojazdów kolejowych nie istnieją międzynarodowe regulacje dotyczące badań ruchowych, w tym w szczególności dla warunków bezpieczeństwa przed wykolejeniem. W związku z tym opracowano nową, uniwersalną metodykę badań symulacyjnych kryteriów bezpieczeństwa przed wykolejeniem pojazdów tramwajowych, bez względu na konfgurację nadwozi danego tramwaju, typu wózka czy szerokość toru. Zaprezentowano założenia nowej metodyki oraz przeprowadzono symulacje dla kilku popularnych na rynku konfguracji tramwajów. Porównano wyniki, otrzymane dla pojazdów z klasycznymi zestawami kołowymi oraz dla pojazdów wyposażonych w zestawy kołowe z niezależnie obracającymi się kołami.

Pojazdy tramwajowe, układy biegowe, symulacje, zestawy kołowe z niezależnie obracającymi się kołami

Trams with independently rotating wheels (IRW) enable to increase a comfort of traveling by lowering the floor level along the entire length of the vehicle, in particular above the bogies. In these trams such solution imposes a different design of motor bogies. In this construction of the bogies, four independent motors mounted on the bogie frame are connected each by a gear-stage with a single running-wheel. By means of the appropriate control algorithm guiding driving torques in curved sections of the railway track can be generated. Trams must ensure a high level of safety of passengers, and one of its aspect is safety against derailment. This article presents an original simulation method to investigate a level of safety against derailment for such vehicles. Principles of this method are independent of the tram car configuration. Using this approach, structural analysis of trams was carried out, which tested drive control in the boogie equipped with independently rotating wheels. Here, numerous simulations of motion on curved tracks were performed by means of various wheel drive control algorithms.

research safety, safety against derailment, derailment of trams, trams with independently rotating wheels, independently rotating wheels

In In the paper, a new proposal of simulations safety against derailment for a tramway vehicles with an arbitrary configuration of wagons and running gears is presented. The existing European standard EN 14363 [1] covers all necessary tests for different railway vehicles, but it is inadequate for tramway vehicles, especially in safety against a derailment examination. Its operational conditions are much different. Tramways overcome horizontal curves with much smaller radii than railway vehicles. There is a large diversity in wheel-rail pairing, i.e. almost every public transport operator uses a different wheel profile. Apart from standard vehicle configuration, i.e., a carbody on two bogies, in modern tram designs varoius arrangements are applied. The described problems suggest that the methodology of safety testing before derailment described in the EN 14363 standard cannot be used without any modifications in the case of testing tramway vehicles.
Based on the obtained computational results, an essential influence of various municipal tramway vehicle designs and configurations on wheel-rail contact forces, in particular, on the derailment factor Y/Q, is discussed. The simulation results confirm the assumption that the track conditions for safety against derailment described in standard [1] addressed to the railway vehicles are not suitable for investigations of the light municipal trams. Moreover, one can remark that relatively low travelling speeds of trams do not guarantee a sufficient safety against derailment with specific vehicle configuration and extreme track geometry (small arc radius and zero cant). Such observations cause the need for further analysis of the discussed topic.

tramway dynamics, safety against derailment, Simpack Rail, MBS

Existing European standard EN 14363 covers all necessary tests for different railway vehicles, but it is inadequate for tram vehicles, especially in safety against a derailment examination. Its operational conditions are much different. Trams overcome horizontal curves with much smaller radii than railway vehicles. There is a large diversity in wheel-rail pairing, i.e. almost every public transport opera-tor uses a different wheel profile. In the running gear design much more rubber-metal elements are used in order to ensure a low-floor interior and to keep the kinematic envelope. Apart from standard vehicle configuration, i.e., a carbody on two bogies, in modern tram designs numerous arrangements are applied: wagons with one outer bogie, wagons with one centered bogie, wagons without bogies (sedan) etc., where twisting shims cannot be used to achieve the required twist. It should be also mentioned that in the low-floor trams there are frequently applied independently rotating wheels (IRW) which are individually driven. The dynamic behaviour of the trams equipped with the IRW wheelsets is significantly different from that of the vehicles with the classical wheelsets. The described issues imply that the methodology of safety against derailment described in EN 14363 stand-ard cannot be applied without any modifications. This paper presents a new pro-posal for a simulation safety against derailment for a vehicle with an arbitrary configuration of wagons and running gears. The numerical analyzes have been performed be means of the SIMPACK software.

safety against derailment, tram vehicle, numerical simulation, run-ning dynamics, SIMPACK software