DC Stray Current in Rail Transit Systems and Cathodic Protection [History]

Stray current is current that seeks unintended paths through earth and metallic utilities. This current can be from a dc or an ac source. Stray current from an ac source is expected to only produce 1-5% of the corrosion produced by an equivalent amount of dc source. Cathodic protection (CP) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell [6]-[8], [11]-[13], [15], [20].