Study on track dynamic forces due to rail short-wavelength dip defects using rail vehicle-track dynamics simulations

A rail vehicle-track interaction dynamics model has been applied to determine the track vertical dynamic forces due to rail shortwavelength dip defects such as squat, dip joints and welds, etc., which are required in both rail vehicle acceptance procedure and track maintenance. The model is validated using the field measurement data of rail squat defects and accelerations on a vehicle axlebox. The simulated track dynamic forces — the P2 forces due to rail dipped joints have been compared with those calculated by using a well-known formula. The results are compared and the formula’s limitations have been discussed. The dependence of the track vertical dynamic forces on the rail dip defect size and vehicle speed has also been investigated.