The glued-insulated joint rail (a special rail used for insulation joints in long-rail sections) has contributed to savings in the manpower needed for maintenance work. However, the rail requires measures to prevent issues that have arisen in recent years, such as failure stemming from corrosion holes on the bottom of the fishplate, separation of adhesives and the deterioration of insulating materials. The RTRI has therefore developed an improved glued insulated joint rail for bonding fishplates that features superior corrosion prevention. A Teflon sheet boundary surface formed in the adhesion layer prevents corrosion of the fishplate metallic base (Fig. 1). A fluid adhesive inserted into the void of bolt holes also prevents infiltration by rainwater, thereby significantly improving insulation performance (Fig. 2).
   To evaluate the applicability of this rail joint for practical purposes, the RTRI performed a fatigue test by repeating loading on a specimen two million times, thus confirming sufficient durability. After the fatigue test, the specimen was disassembled to allow observation of the adhesion layer. Its condition was found to be satisfactory in that separation from the boundary surface had not developed, and the metallic base was not exposed or rusted. As a result, the RTRI was able to confirm the coating effect of the adhesive against failure and insulation deterioration in fishplates (Fig. 3).