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- Burrow, Michael, et al.
(författare)
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Track stiffness considerations for high speed railway lines
- 2009
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Ingår i: Railway Transportations: Policies, Technology and Perspectives. - Hauppauge, NY : Nova Science Publishers. - 9781606928639 - 1606928635 ; , s. 425-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This book provides the latest scientific research regarding the importance of infrastructure charges in establishing competitive conditions in the railway market. The current charging regimes applied throughout the EU member states are analyzed as well as the planning and scheduling that determine how and when the company's resources will be used in the case of railway organizations. Railway noise emission and its reduction are considered among the most important topics in the future development of transportation systems. This book gives an overview on the noise emitted by wheels and rails from the basic emission mechanisms up to noise attenuation by means of passive/active control. The importance of the vertical track stiffness as a means to guide railway track bed design for high speed railway lines are discussed as well. A rational approach to substructure design is described, which it is hoped will further an understanding of the process of appropriate track design and enable the adaptation of existing design procedures to provide a realistic design for the conditions at hand.
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| 8. |
- Dahlberg, Tore, 1945-
(författare)
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Moving force on an axially loaded beam - With applications to a railway overhead contact wire
- 2006
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 44:8, s. 631-644
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Tidskriftsartikel (refereegranskat)abstract
- Using modal analysis, the deflection of a beam subjected to an axial tensile force N and a moving vertical force P , has been determined. This solution was exploited in a study of deflection and wave propagation in the contact wire of a railway overhead catenary system. For moderate values of speed c of the moving force P ( i.e ., c less than half the lowest critical speed c crit ) travelling waves reflect at the boundaries of the contact wire so that the waves meet and catch up with the moving force several times. In practice, when a pantograph (here modelled by the force P ) touches the contact wire some distance from the end of the wire, waves are sent out both in the forward and backward direction, giving even more reflections and wave interactions with the contact force. These waves will add or subtract to the wire deflection at the point of force application. The stress in the wire due to bending is estimated and it appears to be moderate for the speeds investigated here ( i.e ., for c < 0.5ccrit). Close to the critical speed, however, bending stresses will be significant.
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| 9. |
- Dahlberg, Tore, 1945-
(författare)
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On the Use of Under-Sleeper Pads in Tracks with Varying Track Stiffness
- 2009
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Ingår i: Proc 9th International Heavy Haul Conference, June 2009, Shanghai, P R China. - Beijing, China : China Railway Publishing House. ; , s. 293-299
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Konferensbidrag (refereegranskat)abstract
- The track stiffness experienced by a train will vary along the track. Sometimes the stiffness variation may be very large within a short distance. One example is when an unsupported sleeper is hanging in the rail. Track stiffness is then, locally at that sleeper, very low. At insulation joints the bending stiffness of the rail has a discontinuity. A third example of an abrupt change of track stiffness is the transition from an embankment to a bridge. The variations of track stiffness will induce variations in the wheel/rail contact force. This will intensify track degradation such as increased wear, fatigue, track settlement due to permanent deformation of the ballast and the substructure, and so on. In the work reported here the possibility to smooth out track stiffness variations by use of under-sleeper pads is discussed. It is demonstrated that the wheel/rail contact force variations can be made small by modifying the stiffness variations along the track.
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| 12. |
- Dahlberg, Tore, 1945-
(författare)
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Railway track stiffness variations - consequences and countermeasures
- 2009
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Ingår i: Proc of the 2nd International Conference on Recent Advances in Railway Engineering. - Teheran : Iran University of Science and Technology. ; , s. 38-46
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The track stiffness experienced by a train will vary along the track. Sometimes the stiffness variation may be very large within a short distance. One example is when an unsupported sleeper is hanging in the rail. Track stiffness is then, locally at that sleeper, very low. At insulated joints the bending stiffness of the rail has a discontinuity implying a discontinuity also of the track stiffness. A third example of an abrupt change of track stiffness is the transition from an embankment to a bridge. At switches both mass and stiffness change rapidly. The variations of track stiffness will induce variations in the wheel/rail contact force. This will intensify track degradation such as increased wear, fatigue, track settlement due to permanent deformation of the ballast and the substructure, and so on. As soon as the track geometry starts to deteriorate, the variations of the wheel/rail interaction forces will increase, and the track deterioration rate increases. In the work reported here the possibility to smooth out track stiffness variations is discussed. It is demonstrated that by modifying the stiffness variations along the track, for example by use of grouting or under-sleeper pads, the variations of the wheel/rail contact force may be considerably reduced.
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| 16. |
- Dahlberg, Tore, 1945-
(författare)
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Track Issues
- 2006
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Ingår i: Handbook of Railway Vehicle Dynamics. - New York : Taylor & Francis Group. - 0849333210 - 9780849333217 ; , s. 143-179
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Understanding the dynamics of railway vehicles, and indeed of the entire vehicle–track system, is critical to ensuring safe and economical operation of modern railways. As the challenges of higher speed and higher loads with very high levels of safety require ever more innovative engineering solutions, better understanding of the technical issues and use of new computer based tools is required. Encompassing the field from historical development to state-of-the-art modeling and simulation methods, Simon Iwnicki’s Handbook of Railway Vehicle Dynamicssets a new standard of authority and practicality in the study of railway vehicle dynamics.Drawing on the experiences and research of leading international experts, this critical reference surveys the main areas of railway vehicle dynamics. Through mathematical analysis and practical examples, it builds a deep and functional understanding of the wheel–rail interface, suspension and suspension component design, simulation and testing of electrical and mechanical systems, interaction with surrounding infrastructure, and noise and vibration. In-depth discussions deconstruct the components of both vehicle and track systems, explain their contribution to dynamic behavior, and evaluate the advantages and disadvantages of various practical solutions. The book also considers the unique issues of railway tribology, gauging, and derailment.Coverage of computer models, test procedures, roller rigs, and scale testing completes this essential handbook. Whether for the newcomer or the seasoned professional, the Handbook of Railway Vehicle Dynamics is an indispensable tool for modern railway vehicle design.
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| 21. |
- Lundqvist, Andreas, et al.
(författare)
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Railway track stiffness variation - consequences and countermeasures
- 2005
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Ingår i: 19th IAVSD Symposium of Dynamics of Vehicles on Roads and Tracks, 2005. - Milano : Dept Mech Eng, Politecnico di Milano.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The track stiffness experienced by a train will vary along the track. Sometimes the stiffness variation can be very large whitin short distances. These changes in track stiffness will cause variations in the train/track interaction forces, and force variations will normaly imply settlements of the track as a result of permanent deformation in the ballast and in the underlying structure.Since the behaviour of the ballast and subground material is not exactly the same under all sleepers. and since the loading of the track is irregular. the amount of settlement will differ from one sleeper to another. As soon as the track geometry starts to deteriorate, the variations of the train/track interaction force increase, and this speeds up the track deterioration rate.This paper discusses how the transition zone between two track stiffnesses should be designed to reduce the track settlement. The transition from one track stiffness to another is optimized to obtain a wheel/rail contact force with as small variations as possible. A smooth wheel/rail contact force at the transition area will minimize the track settlement.
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