Optimizing Fastening Systems Characteristics to Prevent Stray Current at Urban Tracks

Abstract Stray current in urban railway systems presents a significant challenge, including localized corrosion of rails, fastening systems, and adjacent metal structures, which compromises infrastructure safety. This study focuses on enhancing the resistance of rail fastening systems to mitigate stray current. Laboratory tests were conducted on samples where rails were fixed using two different fastening systems. During testing, the samples were subjected to 26 VDC, and electrical resistance and potential distribution were measured under controlled conditions. The results indicated that both systems were inadequately insulated, resulting in stray current, although in one system the anchor bolts were insulated primarily to prevent current leakage into the track substructure. Material analysis showed that the elastomeric elements in this system were not specified for high electrical resistance, so stray current was not prevented. Modifications for both systems were proposed to improve stray current prevention and were analyzed using numerical models in COMSOL Multiphysics software. The study highlights the importance of establishing precise requirements for the electrical resistance of fastening systems and developing a standardized methodology for measuring resistance.