Variation of effective frictional coefficient at wheel-rail contact interfaces during high speed railway operations

Abstract

Numerical simulations were performed for the analysis of wheel-rail interactions in high speed railway networks, and the variation of effective frictional coefficient at the wheel-rail interface during high speed train operations was quantified, with respect to the increase in speeds of trains. The analyses were performed for railway operations ranging from speeds of 160 to 200 km/h, which are the maximum speeds recommended by Indian Railways for safe operation of trains in the broad gauge railway tracks in India. Transient structural analyses were performed using ANSYS, and it was observed that the interface frictional coefficients at wheel-rail interface had a trend to decrease with an increase in the speed of train. This reduction in the coefficient of friction at wheel-rail interface would contribute to a loss of traction due to reduced grip, resulting in locomotive wheel-slips, wastage of motive power and reduced braking efficiency of train wheels on rails during high speed railway operations. Electronic wheel-spin detectors shall be used to control and alter the power supplied by high speed locomotives to train wheels, for maintaining sufficient traction on the rails. Modification of rail and wheel surfaces using friction modifiers will help in maintaining the frictional grip necessary for maintaining safety in railway operations at the targeted maximum speeds of train transit.