Design, wheel-rail interaction and testing of an innovative reinforced smooth transition insulated rail joint

Insulated Railway Joints (IRJ) fail mainly because of repeated shocks in the end post region, characterized by a largely reduced stiffness, causing loss of insulation (lipping), star cracks in the fishbolt holes and eventually broken rails leading to possible derailments. Laboratory tests to qualify IRJs are inadequate as they do not replicate impact loads. An innovative, reinforced joint named ABJ, made of forged shallow depth switch rails with a long, inclined cut and a thick reinforcing steel baseplate is introduced in the paper. It doesn't show a dip angle in the transition area, resulting in smooth wheel-rail transition forces preventing rail damage, impact noise, vibrations and ballast deterioration. It is designed to be laid on standard sleepers and it can be installed on standard track. An innovative cable routing allows plain and continuous tamping operations optimizing track behaviour and degradation in the long term. Impact noise typical of rail joints is eliminated and the estimated life is theoretically infinite. The paper describes the static and dynamic behaviour of the ABJ as well as the wheel-rail interaction obtained by numerical simulations and a partial full-scale validation of the new joint.