LIGHT RAIL TRANSIT STRAY CURRENT CONTROL: HOW MUCH WATER LINE PROTECTION IS REALLY NEEDED?

摘要

Modern-day DC powered light rail lines are designed with many effective stray current control features built-in, principally an electrically ungrounded traction power negative return circuit. This often includes track construction measures intended to establish much higher track-to-earth resistances when compared to the streetcars of long ago. This attribute dramatically reduces stray current leakage to tolerable levels with limited if any negative impact on underground pipeline corrosion control. Case histories of water pipelines constructed near light rail lines built within the last nine years are reviewed. Results of field evaluations in Sacramento, Salt Lake City and Minneapolis are presented. Guidelines for stray current corrosion protection strategies for ductile iron pipelines are provided.