Advanced Technology for the Identification of Stray Current and Measurement of Track Resistance for DC Powered Rail Systems

Abstract Stray current corrosion that results from the operation of electrified DC transit systems has been an issue for decades, with agencies spending significant sums to address it. Stray currents are known to greatly accelerate the corrosion of metallic infrastructure and can lead to failures if left unchecked. They not only affect the operation of transit agencies, but can also impact external infrastructure, leading to regulatory issues and unforeseen direct and indirect costs. For many electrified railways, the running rails serve as the return path for DC electrical current to the substation. Electrical isolation of the rails is crucial to prevent the current leaking into the adjacent infrastructure. While various solutions exist to measure stray current and track insulation over longer sections of rail, these solutions are limited in their ability to efficiently identify the precise location where the leakage is occurring. This paper describes the recent development of a new technology that significantly reduces the time to locate and address track insulation faults, by identifying the severity and location of stray current along the length of rail. This innovative tool has successfully demonstrated value on multiple operating rail systems and examples from field test campaigns are included to demonstrate this capability.