MODEL LING OF PASSENGER RAILWAY VEHICLE WITH DIFFERENT TYPES OF BOGIE AND EVALUATION OF PERFORMANCE PARAMETERS

Abstract

There has been renewed interest in rail transportation driven by the need for alternatives to congested highways and environmental concerns. The conventional railway vehicle designed for operation at high speed of approximately 200 km/hr makes use of stiff primary suspension elements to provide good dynamic stability. The curving performance of such a vehicle is poor because of wheelset misalignment in curves resulting in increased wheel and rail wear. This increases the maintenance cost. The wheelset misalignment also leads to increased lateral forces which raise the potential for derailment due to wheel climb. The trend towards higher rail vehicle speeds generally results in increased vibrations in the carbody, which has a negative impact on ride comfort. One of the aspects of the railway bogie design that needs improvement is better compatibility between dynamic stability at high speeds and the ability of the vehicle to steer around curves. Carbody vibrations can be reduced either by focusing on structural stiffness of system or by optimising the damping components. This report summarizes the performance parameters of passenger railway vehicle like forces developed in the contact patch between the wheel and rail, stability of axle on tangent track, wear, derailment, ride comfort & rolling contact fatigue. The ways that these parameters govern the behaviour of a vehicle running on straight and curved track are explained and the methods commonly used to calculate these parameters are summarized. As an illustration, the results of passenger railway vehicle with ICF coach & LHB coach from computer simulation has been presented and examined. In the present study passenger railway vehicle with ICF bogie and LHB bogie are modeled as a single car according to Indian railway standards using GENSYS multi-body simulation software. ICF bogie has been modelled with primary suspension between axlebox and bogie, secondary suspension between carbody and bogie, whereas in LHB bogie yaw dampers have been provided between carbody and bogie center. The performance parameters has been evaluated for these two configurations in terms of stability, track forces, derailment, wear, ride comfort & rolling contact fatigue. Result shows that ICF coach is more stable than the LHB coach, whereas the travelling distance before replacing wheelset is lower. Wear on curved path for same speed is more in ICF coach than LHB coach. Rolling contact fatigue for LHB bogie is lower than ICF bogie for same speed.