Numerical investigation of the transient wheel-rail impact behaviour in high-speed turnouts caused by a bonded insulated rail joint

Bonded insulated rail joints (Bonded IRJ) are essential to insulate rails and ensure normal operation of track-circuit signalling. Therefore, bonded IRJs cannot be replaced by the continuously welded joints and are widely existing in high-speed turnouts, by which the wheel-joint impact has been severely threatening the ride safety and comfort. Few researchers are concerned about how the damaged bonded IRJ deteriorates the wheel-rail contact behaviour in high-speed turnouts. To this end, this paper proposed a transient wheel-rail impact model based on the actual irregularities. Results show two different wheel-rail impact modes. The concave shape of the irregularities will induce the discrepancy of impact position when the running speed varies, thus the increase in speed causes the peak wheel-rail force to decrease in downward impact mode as opposed to upward impact. Besides, wheel-joint impact induces greater contact stress and area of contact patches in the vicinity of the end-post, contributing to wider light bands which are consistent with the on-situ conditions. Therefore, the proposed wheel-bonded IRJ impact model can provide guidance in the research of RCF and wear on bonded IRJ, explore the forming reason of the depression and provide a valuable reference for maintenance or damage detection of bonded IRJ.