Bonded Together in Better Joint Quest

An important part of a railroad’s signaling and safety system are the bonded insulated joints that provide track circuits, detect rail breaks and control signal traffic blocks on heavy axle-load lines. This article looks at the latest improvements in the quest for better joints. The author describes 28 prototypes of bonded joints undergoing testing at the Transportation Technology Center Inc. in Pueblo, Colorado. Early results show supported joints lower deflection and epoxy shear stress, and joints with Kevlar insulaters last longer than those with fiberglass insulators. The author also describes a liner which features a high-strength insulating material that reduces joint deflections by 30 percent compared to a current production bonded joint. Additional insulated rail joints are also described.