I live next to Busby Junction and I have been following the electrification works with interest. Last night, I had taken a walk up to a bridge, near my house, that overlooks the line when I noticed five rusted cylindrical shells beside the lines. They were not there when I walked up to the bridge last Wednesday and more work was done at the weekend. I have attached a photo of said shells. What are they? Are they connected to the electrification work and if so, what is their purpose?