VAMPIRE® Published Papers
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Simulation of traction and curving for passive steering hauling locomotives
In a heavy haul train operations the ruling grades that set the tractive power requirements for train consists are often associated with tight curvatures. Past studies of passive or active bogie steering developments have been mostly directed towards high-speed rail applications or light rail and commuter rail applications and hence studies have focused on two axle bogies. Linked passive steering three axle locomotive bogies such as produced by General Motors Electric Motor Division for the SD70 class locomotive are in widespread use however, there are few publications on traction and curving, and few papers on linked passive steering bogies.
This paper presents a simulation study three axle bogie locomotives on various curve radii with traction and variable rail friction conditions. Curving performance is assessed showing body linked radial bogies to have considerable advantages over axle linked bogies that are significantly better than yaw relaxation bogies at improving steering under traction. As traction adhesion approaches the rail friction coefficient steering performance of all bogies without forced steering deteriorates to the same levels as a rigid bogie.
Published in: Proc. IMechE Vol. 222 Part F: J. Rail and Rapid Transit
Author(s): S A Simson and C Cole
Parametric simulation study of traction curving of three axle steering bogie designs
The development of self-steering bogies in locomotives has occurred without extensive study of traction curving bogie dynamics. It is reported that these bogies are unable to steer at high tractive effort levels with the performance essentially the same as rigid bogies. This is due to the required adhesion level approaching wheel rail friction limits and causing creep saturation. Reassessment of the curve steering task in a hauling locomotive has identified that existing concepts of perfect steering [R.M. Goodall and T.X. Mei, Chapter 11: Active suspensions, in Handbook of Railway Vehicle Dynamics, S. Iwnicki, ed., Taylor & Francis Group, Boca Raton, FL, USA, 2006], [R.M. Goodall, S. Bruni, and T.X. Mei, Concepts and prospects for actively-controlled railway running gear,Vehicle Syst. Dynam. 44, supplement 1 (2006), pp. 60–70] are not appropriate for high traction loads in hauling locomotives. An extensive parametric simulation study has been conducted on steering bogie designs for hauling locomotives. Testing of passive steering bogie designs have shown superior performance from forced steering bogies where steering is only partially dependant on wheel rail creep forces. New active steering bogie designs have been proposed [S. Simson, Railway bogie, Australian Provisional Patent Application No. 2007900891, 2007] where steering control is independent of wheel rail creep forces. The new designs combine force steering of wheelsets with secondary yaw activation. The parametric study shows that new active steering bogie designs give superior steering performance under traction.Published in: Vehicle System Dynamics, Vol. 46, Supplement, 2008, 717–728
Author(s): S. Simson, C. Cole
Simulation of Curving at Low Speed Under High Traction for Passive Steering Hauling Locomotives
Presented at: Details uknown
The traction control in modern electric and diesel electric locomotives have allowed rail operators to utilise high traction adhesion levels without undue risk of damage from uncontrolled wheel spin. At the same time some locomotive manufacturers have developed passive steering locomotive bogies to reduce wheel rail wear and further improve locomotive adhesion performance on curves, . High locomotive traction loads in curving are known to cause the loss of steering performance in passive steering bogies , , . At present there are few publications on the curving performance of locomotive steering with linkage bogies . The most extreme traction curving cases of low speed and high adhesion for hauling locomotives have not been fully investigated with effects of coupler forces and cant excess being generally ignored , , .
This paper presents a simulation study for three axle bogie (co-co) locomotives in pusher and pulling train positions on tight curves. The simulation study uses moderate and high traction adhesion levels of 16.6% and 37% for various rail friction conditions. Curving performance is assessed showing forced steering (body linked radial) bogies to have considerable advantages over self steering (linked axle yaw) bogies. Likewise it is shown that self steering bogies are significantly better than yaw relaxation bogies at improving steering under traction. As the required traction adhesion approaches the rail friction coefficient, steering performance of all bogies degrades and yaw of the bogie frame relative to the track increases. Operation with excess cant and tensile coupler forces are both found to be detrimental to the wear performance of all locomotive bogies increasing the bogie frame yaw angles. Bogie frame pitching is also found to have significant effect on steering causing increased performance differences between bogie designs.
Author(s): S.A. Simson and C. Cole
Wheel rail contact foces prediction and validation with field tests
Field testing of the wagon health card was completed using the RailCorp AK Track recording car. The wagon health card device was installed on the AK Car to allow the device to be tested and compared with the measured track data and AK car vehicle responses. As wheel rail contact forces cannot be measured directly these were calculated using VAMPIRE simulation. An inverse model with parameters matching the AK Car was embedded in the wagon health card device. The inverse model had been developed in earlier research to predict wheel rail contact forces using only measurements of car body responses; lateral and vertical accelerations, roll, pitch and yaw angular velocities. The device tested was also a proof of concept test for an integrated device with all transducers mounted within the one small ‘black box’. Testing was completed in January 2007 on the Parks-Cobar section in NSW. The following paper presents the results and discusses the difficulties in validation without direct wheel-rail contact force measurements. The results for estimating vertical contact forces were quite encouraging and acceptable for a proof of concept device. There was significant difference in lateral predictions and hence L/V ratios probably due to differences between assumed and actual wheel profiles.Presented at: Conference On Railway Engineering, Perth 7-10 September 2008
Author(s): Fujie Xia , Colin Cole, and Peter Wolfs
An active steering bogie for heavy haul diesel locomotives
The steering task for heavy haul locomotives can involve high levels of tractive effort during curving on steep gradients. Traction curving has been reported as problematic for current steering locomotive bogies , , . The Centre for Railway Engineering (CRE) has been investigating traction steering performance. Improvements in traction steering performance will produce more efficient rail transport. Simulations involving curving and hunting evaluations have been completed for a wide range of traction bogie designs. A new bogie design concept is proposed involving yaw actuation of the bogie frame with forced steering linkages (AY-FS Bogie). Simulation tests have shown this concept able to reduce traction curving wear by 61% from improved steering under traction. The bogie concept is also capable of high speed stability performance. AY-FS bogie has further advantages over AWY bogie designs,  in that none of the actuation equipment or sensors for AY-FS bogie’s need to be mounted on the bogie frame. Further development of the research is needed with a prototype design simulation testing to optimise the suspension settings and control design for optimised performance.Presented at: Conference On Railway Engineering, Perth 7-10 September 2008
Author(s): Scott Simson and Colin Cole
Control alternatives for yaw actuated force steered bogies
Presented at: Proceedings of the 17th World Congress, The International Federation of Automatic Control, Seoul, Korea, July 6-11, 2008
A new design for actively steered bogies (Simson S., 2007) has been proposed for tractive rollingstock to improve not only wheel rail wear and rolling contact fatigue but to also improve wheel rail adhesion. The new bogie design features forced steering with active yaw control of the secondary suspension.
The control alternatives for the new bogie design are limited by the need for the control to act independently to wheel rail creep forces. Two control alternatives are presented, a full active method where the control is applied based on known track alignment and the vehicles position. And a semi active method where the track curvature is estimated from gyroscope inputs with no prior knowledge of the track and a target alignment is estimated.
Author(s): Scott Simson, Colin Cole
Optimising the Wheel/Rail interface on a modern urban rail system
The Kowloon-Canton Railway has opened two new suburban rail routes in Hong Kong. Initially, these lines used the high-conicity P8a wheel profile and the UIC60 rail profile. Problems were experienced with the wheel/rail interface, including disappointing wheelset life, high vibration due to hunting instability and rapid growth of rolling contact fatigue damage on the high rail in curves. Careful analysis using established wheel/rail interface modelling techniques and innovative validated rolling contact fatigue prediction algorithms has led to development of an optimised wheel/rail interface. The combination of the low-conicity P8y wheel profile and the CEN60-E2 rail profile, with effective lubrication, has given substantial improvements in re-profiling intervals, improved running stability and a massive reduction in rolling contact fatigue damage.Published in: Vehicle System Dynamics, Volume 46, Issue S1 & 2 2008 , pages 119 – 127
Author(s): J.R. Evans, T.K.Y. Leeb and C.C. Hon
A New tool for planning vehicle dynamics based track maintenance
Presented at: Railway Engineering 2007 – 9th International Conference and Exhibition, University of Westminster
An important part of railway track maintenance planning is concerned with reducing the irregularities in the measured track geometry to maintain safety against derailment and ride quality standards. To increase productivity, various track maintenance planning tools have been developed to assist engineers with this task, however these have traditionally only considered the track in isolation. This paper describes a new off-line tool VIM (VAMPIRE Interaction Manager) for assisting with railway track maintenance in which the dynamic behaviour of railway vehicles is also considered. Using vehicle response data from VAMPIRE (railway vehicle dynamics simulation software), track locations exhibiting the greatest risk of derailment can be identified and track maintenance prioritised accordingly. By considering the vehicle and track as a system problems can be identified that would not normally be apparent by considering the track geometry alone. Track maintenance can be planned in a more systematic manner leading to greater passenger safety and reduced operating costs.
Simulated vehicle response data, used by the new tool, can be generated for user specified running conditions. Vehicle type, wheel/rail contact and running speed can be varied, allowing risk assessments to be produced for current and future vehicles using predetermined exceedence thresholds. In addition to its use by track maintenance engineers, this tool can also be used by vehicle manufacturers to assess derailment risk and offers the potential to assess ride performance, track forces and other vehicle/track interaction issues of new vehicle designs.
Author(s): Dr Catherine Grimes, Dr Geoff Hunt, Mr Stephen Wilson
A review of modelling methods for railway vehicle suspension components
The dynamics behaviour of railway vehicles has been the subject of study for over a century but the advances in computing technology in the last few years have led to a very rapid development in the use of numerical techniques for solving railway vehicle dynamics problems. As these techniques have developed, and have been applied to ever more complex problems, the modelling of the vehicle components has increased in importance. Mathematical models of railway vehicles may now include components such as swing links, air-springs, trailing arm suspensions, load sensative friction dampers, rubber bushes with hysteresis etc, all of which require sophisticated modelling techniques to produce accurate results. This paper looks at the developments that have taken place in this area, the background to the need for sophisticated models, the improvements in accuracy that can result and some of the difficulties in applying these techniques to the modelling of real situations.Published in: Vehicle System Dynamics, Volume 24, 1995 , pp. 469 – 496
Author(s): B.M. Eickhoff, J.R. Evans, A.J. Minnis
Validation of dynamics simulations of rail vehicles with friction damped Y25 bogies
Theoretical modelling of a container wagon fitted with Y25 bogies was compared to actual track test data, using the VAMPIRE Rail Vehicle dynamics modelling software. The Y25 bogie makes use of load sensative friction damping, and has highly non-linear behaviour. Elements of the vehicle design which were important in predicting vertical and lateral ride were identified and are described in the paper. Wheel profile, accurate modelling of primary and secondary suspensions, and coefficients of friction of the wheel/rail interface and suspension friction faces, were found to be particularly important to ride prediction. The behaviour of the vehicle was very input dependent. It was possible to produce a good correspondance between trac test and model results for both vertical and lateral behaviour.Published in: Proceedings of the I MECH E Part F Journal of Rail and Rapid Transit, Volume 222, Number 3, 2008 , pp. 255-265
Author(s): J.R. Evans, P.J. Rogers
Simulation of curving at low speed under high traction for passive steering haulage locomotives
Published in: Uknown details
The traction controls in modern electric and diesel electric locomotives have allowed rail operators to utilise high traction adhesion levels without undue risk of damage from uncontrolled wheel spin. At the same time some locomotive manufacturers have developed passive steering locomotive bogies to reduce wheel rail wear and further improve locomotive adhesion performance on curves. High locomotive traction loads in curving are known to cause the loss of steering performance in passive steering bogies. At present there are a few publications on the curving performance of locomotive steering with linkage bogies. The most extreme traction curving cases of low speed and high adhesion for hauling locomotives have not been fully investigated with effects of coupler forces and cant excess being generally ignored.
This paper presents a simulation study for three axle bogie (co-co) locomotives in pusher and pulling train positions on tight curves. The simulation study uses moderate and high traction adhesion levels of 16.6% and 37% for various rail friction conditions. Curving performance is assessed showing forced steering (body linked radial) bogies to have considerable advantages over self steering (linked axle yaw) bogies. Likewise it is shown that self steering bogies are significantly better than yaw relaxation bogies at improving steering under traction. AS the required traction adhesion approaches the rail friction coefficient, steering performance of all bogies degrades and yaw of the bogie frame relative to the track increases. Operation with excess cant and tensile coupler forces are both found to be detrimental to the wear performance of all locomotive bogies increasing the bogie frame yaw angles. Bogie frame pitching is also found to have significant effect on sterring causing increased performance differences between bogie designs.
Author(s): S.A. Simson, C. Cole
Grey-box based inverse wagon model to predict wheel rail contact forces from measured wagon body responses
A grey-box based inverse wagon model was developed to estimate wheel-rail contact forces using only measurements of wagon body responses as inputs. The project is based on a similar application using a deterministic inverse wagon model. The deterministic (i.e white box) inverse wagon model has some limitations, one of which is that the high frequency components of the forces at the wheel-rail interface cannot be predicted from the lower frequencies at the wagon body. They are effectively isolated the suspension. To overcome this problem the present research focuses on developing of a grey-box based inverse wagon. The high frequency forces that may be considered as the responses to random track irregularities with high frequency and appear as a random feature. The grey-box based inverse wagon is used to predict wheel rail contact forces using only lateral and vertical accelerations, roll, pitch and yaw angular velocities measure on the wagon body.Published in: Vehicle System Dynamics, Volume 46, Supplement 1, September 2008 , pp. 469-479
Author(s): F. Xia, C. Cole, P. Wolfs
Fatigue life evaluation of a railway vehicle bogie using an integrated dynamic simulation
An integrated design methodology has been developed for the fatigue life evaluation of railway vehicle bogies. In principle, there are five parts in the procedure: specification and measurement of track irregularities; modelling railway vehicle and description of rail-wheel profiles; obtaining the railway vehicle suspension load histories; dynamic analysis and stress evaulation of the bogie frame; fatigue life evaluation of the bogie. The whole procedure has been applied to a typical London Underground railway vehicle. The theoretical results have been validates against field test data and fatigue calculations have indicated good agreement with operational data from the actual vehicles. It has been shown that a design methodology for railway vehicle bogies based on the track profiles on which they will run and on thier own structural characteristics is possible and can be used at an appropriate stage in the design process.Published in: Uknown details
Author(s): R.K. Luo, B.L. Gabbitas, B.V. Brickle
Hardware-in-loop simulation of railway vehicles with tilting and active suspension systems
An integrated model has been developed of a three-car tilting train. The model includes full non-linear wheel-rail contact modelling and significant suspension non-linearities. A realistc model of the tilt control system us also included. Simulations are presented of the effect of a number of system parameters on the behaviour of the tilting train. The development of a facility for hardware-in-loop testing of real tilt and active suspension control systems is discussed.Published in: Uknown details
Author(s): Stephen Kent and Jeremy Evans
The application of independently rotating wheels to railway vehicles
Published in: Uknown details
Various potential design of unconventional wheelset have been considered by different organisations in recent years. To avoid confusion the wheels considered by British Rail Research in this study are referred to as independently rotating wheels (IRW), indicating that, while the two wheel of one wheelset are free to rotate at different angular velocities, in all other ways they act as rigid wheelset thus providing problems at track features such as switch and crossing work.
Experimental work using a test coach demomstrated some of the advantages and difficulties associated with such wheels and these have now been investigated in more detail.
Theoretical methods for the prediction of the behaviour of rialway vehicles incorporating independently rotating hweels have been developed and incorporated in the standard BR Research vehicle dynamics program VAMPIRE. Good agreement was obtained between the theoretical methods and the results of the track tests, see for example, giving confidence in the use of predictions to investifate other aspects of independent wheel behaviour. These theoretical methods have been used in the investigations described in this report.
Author(s): B.M. Eickhoff
Comparison of wheel–rail contact codes for railway vehicle simulation: an introduction to the Manchester Contact Benchmark and initial results
A new benchmark is being undertaken to assess the impact of wheel–rail contact modelling assumptions on the simulation of railway vehicle dynamics. The benchmark is split into two distinct simulation cases: the first, Case A, using a single wheelset to pinpoint the differences between the contact models and the second, Case B, using a simplified railway vehicle to assess the effect of the different contact models on the simulation of vehicle behaviour. After an open discussion of the Case A specification, the initial call for contributions was made in November 2006. The discussion of simulation Case B specifications was opened in April 2007 and to date is ongoing. This paper briefly introduces the new Manchester Contact Benchmark and presents some of the initial findings from simulation Case A.Published in: Vehicle system dynamics, 2008, vol. 46, no. 1-2, pp. 129-149
Author(s): P. Shackleton and S. Iwnicki