Rail Wheelset Research Articles

Computation of Slip analysis to detect adhesion for protection of rail vehicle and derailment

Adhesion level for the proper running of rail wheelset on track has remained a significant problem for researchers in detecting slippage to avoid accidents. In this paper, the slippage of rail wheels has been observed applying forward and lateral motions to slip velocity and torsion motion. The longitudinal and lateral forces behavior is watched with respect to traction force to note correlation based on the angle of attack. The deriving torque relation with tractive torque is watched to check slippage. Coulomb’s law is applied in terms of tangential forces to normal forces owing to creep co-efficient and friction to get the adhesion. Nadal’s limiting ratio is applied to escape from wheel climb and derailment from track depending upon wheel profile and flange on straight path and curves.

Step Response and Estimation of Lateral and Yaw Motion Disturbance of Rail Wheel set

The rail wheelset dynamics has skeleton importance to avoid the slip and slide due to insufficient adhesion level depending on creep forces. Proper study and control upon lateral and yaw motion owing to creep forces may reduce the problem at some extent. In this paper, this dynamics of wheelset with its possible degree of freedom has been discussed and limited to lateral and yaw analysis. These analyses have been computed and simulated by simulink to observe their behavior. The disturbances of these dynamical parameters are estimated using Kalman filter. The correlation of actual and estimated curves has been assessed to invent novel idea.

Adhesion Detection Analysis by Modeling Rail Wheel Set Dynamics under the Assumption of Constant Creep Coefficient

Adhesion level control is very necessary to avoid slippage of rail wheelset and track from derailment for smoothing running of rail vehicle. In this paper the proper dynamics of wheelset for velocities acting in three dimensions of wheelset and rail track has been discussed along with creep forces on each wheel in longitudinal, lateral and spin directions has been enumerated and computed for suitable modeling. The concerned results have been simulated by Matlab code to observe the correlation of this phenomenon to compare creepage and creep forces for detecting adhesion level. This adhesion identification is recognized by applying coulomb’s law for sliding friction by comparing tangential and normal forces through co-efficient of friction

A mechatronic approach for effective wheel slip control in railway traction

This article proposes a radically new approach for the detection of wheel slip/slide and re-adhesion control of AC traction motors in railway applications, which provides an important alternative and advantageous technique in traction/braking control systems to maximize the use of adhesion in poor contact conditions. The proposed concept explores the variations in the wheelset dynamic properties caused by the condition changes at the wheel—rail contact, and detects and controls the slip conditions from the dynamic behaviour of a wheelset, indirectly. All the dynamic motions of rail wheelset, which are closely related to wheel—rail contact mechanics, are included in the study; the influence of contact conditions on the relevant modes is assessed, which is essential in the development of a mechatronic solution based on dynamic interactions. This is different from the more general approaches in many other studies on traction controls where the inclusion of only wheelset rotation and longitudinal motions are considered as sufficient. The development of the slip detection and re-adhesion control schemes is presented and comprehensive simulation results are produced to support the proposed idea.

Bond Graph Modeling of Rail Wheelset on Curved Track

This paper presents a bond graph model of a free rail wheelset rolling on fleXible curved track, considering siX degrees of freedom without linearity approXimations. Modeling of engineering systems through bond graphs is based on eXchange of power amongst the basic elements of a system and several energy domains can be represented in a unified manner. In this paper, the modeling approach is based on creating subsystem bond graph models or capsules representing various analytical aspects of wheelset dynamics. The model is finally converted to a wheelset capsule, which can be further used for the development of truck and carbody models with suspension elements. The model can accommodate any creep force formulation for the rail—wheel contact forces. In this work, both Kalker's linear theory and heuristic modification based on non-linear formulation by Vermeulen and Johnson are used separately in a comparative study. Both these formulations allow the creep forces to be modeled by a non-linear bond graph R elements acted upon by the corresponding slip velocities between the wheel and track. Kinematic analysis of the wheelset is carried out to determine velocities of the contact points. The bond graph is created using software SYMBOLS 2000 and simulated for a set of parameter values.

A Systems Approach for Wheelset and Traction Control

SUMMARYThis paper presents the first part of a systems approach for the control of rail wheelset dynamics and traction, which studies interactions between the two sub-systems and explores potential benefits of integrated approaches in terms of the wheelset stability, curving performance and effect of tractive effort. The study is carried out based on a two-axle vehicle configuration developed in a study of the mechatronic approach for rail vehicles. A passively-stabilised vehicle with powered axles is used as a basis for performance comparison, but this paper concentrates upon active control solutions and their effect on the provision of traction.

Hopf Bifurcation and Hunting Behavior in a Rail Wheelset with Flange Contact

An analytical investigation of Hopf bifurcation and hunting behavior of a rail wheelset with nonlinear primary yaw dampers and wheel-rail contact forces is presented. This study is intended to complement earlier studies by True et al., where they investigated the nonlinearities stemming from creep-creep force saturation and nonlinear contacts between a realistic wheel and rail profile. The results indicate that the nonlinearities in the primary suspension and flange contact contribute significantly to the hunting behavior. Both the critical speed and the nature of bifurcation are affected by the nonlinear elements. Further, the results show that in some cases, the critical hunting speed from the nonlinear analysis is less than the critical speed from a linear analysis. This indicates that a linear analysis could predict operational speeds that in actuality include hunting.