Investigation and enforcement of comprehensive lightning protection in Tokyo metropolitan area railway system

In this paper, our policies for lightning protection in electronic and electrical equipments for railway transportation in Tokyo metropolitan area are summarized. Conventionally, we tried to improve lightning protection characteristics in each section such as signaling, communication and power supply section independently. Reflecting the equipments damage in summer of 2008, we reconsidered our countermeasures. Not only the proposed and enforced countermeasures in each section but also comprehensive countermeasures such as total grounding system design will be shown.