It is very significant to setting up lightning protection standard for contact rail

studying on lightning flash-over characteristics of contact rail line along viaduct section. The paper is based on the roiling ball method

the light-ning strike type about metro contact rail are divided. On this basis

building the contact rail model of elevated sectionunder different lightning stroke types

the lightning flashover characteristics under different lightning strike typesare studied

and the influences of pier grounding resistance change on conductor voltage difference are analyzed.The research founds that two types between lightning strikes lightning strip and lightning strike train are prone to oc-cur. When lightning strikes the lightning strip

lightning current level required for insulation bracket flashover

which caused by induced overvoltage of the contact rail is lower than that of ground potential counterattack

so themain reason for the insulation bracket flashover is the induced overvoltage. When lightning strikes the train

thelightning current amplitude reaches 118 kA

which will cause the insulation bracket flashover through the form of in-ducted overvoltage

but the cumulative probability is small

so the probability of lightning strike triggered insulatedguardrail flashover is not high.