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- Brabie, Dan, et al.
(författare)
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An overview of some high-speed train derailments : means of minimizing consequences based on empirical observations
- 2008
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Ingår i: Proceedings of the Institution of mechanical engineers. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097. ; 222:4, s. 441-463
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Tidskriftsartikel (refereegranskat)abstract
- Studies published on rail vehicles' post-derailment behaviour as ameans of minimizing consequences are surprisingly scarce. This paper sets a first step to reduce this lack of knowledge by analysing a collection of incident/accident case studies, with the main focus on the course of events immediately after derailments. This is mainly with respect to whether the train stays upright and close to the track centre-line and is 'safe' or deviates laterally with a probable serious consequence. Accordingly, an empirical database is established containing as much relevant information as possible of past incidents and accidents occurring at speeds over 70 km/h due to mechanical failure close to the running gear/track interface, as well as other causes that ultimately brought the train into a derailed situation. Although two derailments are never the same, certain patterns appeared to emerge based on the descriptions available in each incident or accident report. Mechanical restrictions between axles and bogie frames appear to minimize the risk of derailments after an axle failure on the outside of the wheel. Once derailed, evidence suggests that certain low-reaching parts on the wheelset or the bogie frame may act as substitute guidance mechanisms, thereby minimizing large lateral train deviations. However, for a large number of events, the available information does not allow conclusions based on observations only. This paper is the first in a forthcoming series dealing with the possibilities of minimizing devastating consequences of high-speed derailments by appropriate measures and features in the train design including the running gear.
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| 4. |
- Brabie, Dan, et al.
(författare)
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Dynamic simulation of derailments and its consequences
- 2006
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 44:Suppl 1, s. 652-662
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Tidskriftsartikel (refereegranskat)abstract
- This article describes the necessary prerequisites and methodology in progress for studying train vehicle derailments and means of minimising the risk of catastrophic consequences. A comprehensive model has been developed and used in the multi-body system (MBS) simulation software for studying pre- and post-derailment vehicle behaviour. An axle-mounted brake disc and vertically extended bogie frames have shown empirically, as well as by MBS simulations, a potential to favourably influence the sequence of events in case of wheel flange climbing derailments. The MBS simulation methodology has been presented. Examples of how critical geometrical parameters affect the ability of these mechanisms to act as substitute guidance are presented. Further, a finite element (FE) model is developed for studying the impact phenomenon between a rail vehicle wheel and concrete sleepers. In particular, the proposed FE model will be used for obtaining hysteresis data for the wheel-sleeper force as functions of concrete indentation, for further development of the MBS simulations technique.
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| 5. |
- Brabie, Dan, et al.
(författare)
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High-Speed Train Derailments : Minimizing Consequences through Innovative Design
- 2008
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Ingår i: Proceedings of the World Congress of Railway Research (WCRR'08).
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Konferensbidrag (refereegranskat)abstract
- In the current paper, various possibilities of minimizing consequences of high-speed rail vehiclederailments have been studied through a combination of empirical observations and multi bodysystem (MBS) simulations. In order to assess the appropriate measures and features for an increasedderailment-worthy design, a comprehensive MBS model is developed to predict the pre and postderailmentvehicle behaviour. Preventing wheel flange climbing derailment after axle journal failureson curved track is accomplished by implementing mechanical restrictions in the bogie frame. Threealternative substitute guidance mechanisms are presented and a systematic feasibility analysis forone of them, a low-reaching axle journal box, is presented. Three conventionally coupled passengertrailing cars are investigated after derailments on tangent and curved track as a function of themaximum centre coupler yaw angle, carbody height of centre of gravity, coupler and bogie transversalbeam height. Furthermore, the articulated train concept is investigated as a function of different intercarbodydamper characteristics.
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| 8. |
- Brabie, Dan, 1975-
(författare)
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On Derailment-Worthiness in Rail Vehicle Design : Analysis of vehicle features influencing derailment processes and consequences
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis aims at systematically studying the possibilities of minimizing devastating consequences of high-speed rail vehicle derailments by appropriate measures and features in the train design including the running gear. Firstly, an empirical database is established containing as much relevant information as possible of past incidents and accidents that have occurred at substantial running speeds due to mechanical failure close to the interface between the running gear and the track. Other causes that ultimately brought the train in a derailed condition are also covered. Although various accidental circumstances make each derailment a unique event, certain patterns appear to emerge which lead to several critical vehicle parameters capable of influencing the outcome of a derailment or preventing a derailment to occur. Secondly, the possibility of preventing wheel climbing derailments after an axle journal failure is studied by implementing mechanical restrictions between wheelsets and bogie frame. In this respect, a multi body system (MBS) computer model is developed to account for such an axle failure condition, which is successfully validated on the basis of two authentic passenger car events. In order to study the overall post-derailment vehicle behaviour, in particular the wheelsets’ vertical motion and lateral deviation on sleepers, a comprehensive MBS post-derailment module is developed and implemented in the commercially available software GENSYS. The model detects wheel-sleeper impact conditions and applies valid force resultants calculated through linear interpolation based on a pre-defined look-up table. The table was constructed through exhaustive finite element (FE) wheel to concrete sleeper impact simulations utilising the commercially available software LS-DYNA. The MBS post-derailment module has been validated successfully in several stages, including a correct prediction of the derailing wheelset’s trajectory over ten consecutive sleepers in comparison with an authentic passenger vehicle derailment event. An extensive simulation analysis on the feasibility of utilizing alternative substitute guidance mechanisms attached to the running gear on rail vehicles is presented, as means of minimizing the lateral deviation. Three low-reaching guidance mechanisms attached onto the running gear (bogie frame, brake disc and axle journal box) are analysed in terms of geometrical parameters for a successful engagement with the rail in order to prevent large lateral deviations after twelve different derailment scenarios. Three conventional coupled passenger trailing cars are investigated in terms of lateral deviation and vehicle overturning tendency after derailments on tangent and curved track. This is performed as a function of various vehicle design features and parameters such as: maximum centre coupler yaw angle, carbody height of centre of gravity, coupler height and additional running gear features. In a similar manner, the articulated train concept is investigated in terms of the post-derailment vehicle behaviour as a function of different inter-carbody damper characteristics and running gear features.
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| 9. |
- Brabie, Dan, et al.
(författare)
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On minimizing derailment risks and consequences for passenger trains at higher speeds
- 2009
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - 0954-4097 .- 2041-3017. ; 223:6, s. 543-566
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Tidskriftsartikel (refereegranskat)abstract
- The first part of this article deals with the possibility of preventing wheel climbing derailments after an axle journal failure by implementing mechanical restrictions between the wheelsets and the bogie. A multi-body system (MBS) computer model is developed to account for such an axle failure condition, which is successfully validated by comparing the pre-derailment sequence of events with two authentic cases. An extensive parameter analysis on the maximum vertical and longitudinal play between the wheelset and the bogie, required to prevent a highspeed power or trailer car to derail, is performed for various combinations of running conditions in curves. Once an actual derailment has Occurred on conventional passenger trains at 200 km/h, extensive MBS simulations are performed on the feasibility of utilizing alternative substitute guidance mechanisms, such as low-reaching parts of bogie frame, axle box, or brake disc, as means of minimizing the lateral deviation. Results are presented in terms of geometrical parameters that lead to a successful engagement with the rail for a total of 12 different derailment scenarios. These are caused by an axle journal failure, an impact with a small object on the track, or a high rail failure. Minimizing the lateral deviation is also investigated by means of restraining the maximum Coupler yaw angle and altering the bogie yaw stiffness. Time-domain simulations are also performed in terms of lateral track forces and derailment ratio when negotiating a tight horizontal 'S-curve'. Further, the articulated train concept is investigated in terms of the post-derailment vehicle behaviour after derailments on tangent and curved track at a speed of 200 km/h. In this respect, a trainset consisting of one power car and four articulated passenger trailer cars is modelled in the MBS software. Results in terms of lateral deviation and maximum carbody roll angle are presented as a function of different inter-carbody damper characteristics and running gear features. The feasibility of these damper characteristics is also tested in terms of lateral track forces and derailment ratio when negotiating a tight horizontal S-curve.
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| 10. |
- Brabie, Dan, 1975-
(författare)
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On the Influence of Rail Vehicle Parameters on the Derailment Process and its Consequences
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis aims at systematically studying the possibilities of minimising devastatingconsequences of high-speed derailments by appropriate measures and features in thetrain design, including the running gear. The course of events immediately afterderailments is studied with respect to whether the train stays upright and close to thetrack centre line or deviates laterally with probably serious consequences. There is abelief in the railway community that some trains can better cope with derailment thenothers, although this superiority is apparently hard to quantify.Firstly, an empirical database has been established containing as much relevantinformation as possible of past incidents and accidents occurred at higher speeds due tomechanical failure close to the interface between the running gear and the track, as wellas other causes that ultimately brought the train into a derailed condition. Although nevertwo derailments are the same, certain patterns appeared to crystallise after analysing thecourse of events immediately after the failure based on the descriptions available in eachincident or accident report. Ultimately, this led to that several critical vehicle parameterscould be distinguished as capable to influence the outcome of a derailment.Secondly, two of the critical vehicle features found in the first stage have been subject todetailed analysis by means of multi-body system (MBS) simulations. The first phase ofthe computer simulation program focused on studying the tendency of a wheelset toderail as a result of an axle journal failure on the outside of the wheel. The prederailmentcomputer simulation model has been validated with good results for twoauthentic Swedish events of axle journal failure.Thereafter, one of the newly found critical vehicle feature, the wheelset mechanicalrestrictions relative to the bogie frame, have been extensively studied on an X 2000power unit and trailer car model. The results show that a vertical mechanical restrictionof the wheelset relative to the bogie frame of approximately 50 to 60 mm is capable ofkeeping the wheelsets on the rails after an axle journal failure, for the studied conditions.An axle mounted brake disc constitutes the second critical vehicle feature that has thepotential to favourably influence the sequence of events in cases of wheel flangeclimbing. A minimal range of geometrical parameters for which the rail would safely fillthe gap between the brake disc and the wheel has been calculated.The third and last part of the thesis establishes the prerequisites necessary in order tostudy the remaining of the critical vehicle parameters found in the first part, whichrequires complete MBS simulations of derailed vehicles rolling on track structures, i.e.concrete sleepers. To accomplish this task, hysteresis data for the force as function ofconcrete material indentation, are aimed to be acquired by means of finite element (FE)simulations. Therefore, the intended FE model of wheel-concrete sleeper impact issubjected to a tentative validation procedure. A good agreement is observed whencomparing the FE model results with an authentic accident in terms of concrete sleeperindentation. Furthermore, preliminary results in terms of a wheelset tendency to reboundafter concrete sleeper impact are presented.
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