Analysis of tapered, adhesively bonded, insulated rail joints

This paper investigates a commercially available bonded tapered rail joint that is proposed as a way to reduce the high stresses that may result in the more typical double butt-strap joint configuration. Bonded insulated rail joints typically consist of two steel reinforcing joint bars that are bonded to the rails using an epoxy adhesive containing either a fiberglass or aramid cloth layer. They electrically isolate track sections into discrete blocks that detect the positions of trains. They can also be useful at times in detecting rail breaks. Due to their high replacement costs, there is a strong drive to develop rail joints that have made improvements in durability. The research considers this in two types of analysis. In the first type, a model is developed that analyzes the rails and joint bars as beams while the adhesive and ground are analyzed as distributed elastic springs. For this type of analysis, the Rayleigh-Ritz method is used to obtain numerical solutions. In the second type of analysis, the finite-element method is employed to obtain deflections, bending moments, and stresses. From the analyses the authors conclude that tapered insulated joints offer some advantages (lower deflections, bending moments, and shear stresses in the adhesive) over conventional insulated rail joints.