Apparently that is part of their purpose. When presented with lightning, however, they turn to conductors allowing the lightning to pass to ground. You can see their teardown in video form ...

An curved arrow pointing right. What are those odd looking things you always see attached to power lines? Turns out, they're called lightning arresters and they're crucial to preventing certain ...

However, Tata Power, in its statement, attributed the disruption to a lightning arrestor failure at Central Railway's Chola substation. "The supply issues were due to a lightning arrestor failure ...