Influence of track variables and product design on insulated rail joints

Insulated rail joints are used for signal control and detection of broken rails in railway operations. Bonded insulated rail joints are the standard in freight railroads with heavy axle loads. While there have been many numerical and experimental studies investigating the mechanics of insulated rail joints, mechanisms to understand the impact failure of insulated rail joints require further attention. This study presents a dynamic finite element model designed to simulate the mechanics of an insulated rail joint starting from a wheel-rail contact interface to stresses and deflections at any point under the wheel loads at speeds up to 60 mph. Track configuration and product design options were chosen as input variables for the model. The selection of these variables was driven by the need to answer track engineers' questions about supporting versus suspending joints on wood or concrete ties and responses of different design options to different track configurations. Results show that contact stresses did not change significantly as a result of track configuration. The differential deflection between the two rails right before the impact had a linear correlation with the resulting contact stresses on the rail head. Supporting joints were better at reducing bar stresses, especially on wood ties. Certain product features can greatly influence the bar and the adhesive stresses of the insulated rail joint.