Corrugation Reduction by Semi-Active Track

The wear of wheels and rails is of major concern for every railway and vehicle maintenance authority, since reprofiling and replacing worn wheels and rails absorb a significant part of their maintenance budget. The wear can be divided into several categories based on the result of the wear, such as homogenous wear, corrugation, fatigue, etc. This paper is focused on the corrugation and its reduction. The underground railway network has the particularly to be loaded by vehicles with similar dynamics, similar dimensions, similar weights and running at similar velocities, thus similar responses to the excitations are expected. The proper corrugation mechanism is not well understood. Despite the fact that the corrugation is common for many railway tracks, its main features seem to be rather different from one to another, specific for a given track and vehicle fleet. According to hypothesis found in literature, the corrugation occurs as a result of longitudinal slip between wheel and rail supported by variation of track impedance. Some eigenmodes of the vehicle-track system are excited, which cause corrugation wear. Higher speeds (high-speed railways) as well as low axle loads (underground railways) encourage the growth of corrugation. The corrugation is usually observed in areas where high contact vibrations with slip are present. There are particularly two basic locations (i) curves and (ii) traction and braking areas. The corrugation propagation in the curves, mostly of small radius, is excited by the difference in the path length for the left and right wheel. The difference is just partially compensated by the conicity of the wheels. The possible solutions to decrease rail and wheel wear are summarised to three categories: (i) maintenance of tracks and vehicles, (ii) track design, and (iii) vehicle design. The basic phenomenological simulation model is implemented. The model is used to investigate possible explanation of the corrugation formation. The simulation parameter study performed with the phenomenological model is presented. The application of semi-active technology in order to decrease corrugation propagation is discussed. The semi-active track and its control is modelled and simulated. The preliminary results indicate that semi-active sleepers are able to decrease corrugation propagation significantly