It's green, it's porcelain, and it's from Italy. But it doesn't look like a normal insulator. Any ideas?

UPDATE: I have an answer for this one, but I'll hold off a couple days and see if anyone else can figure it out. (Here's another clue for you all, the Walrus is Paul...) Hint #1: It is indeed an insulator. Hint #2: There are two of these "hats" and a center "spool" in the assembly, plus some metal brackets, and a rod passing through all three parts. Hint #3: There are no wires directly connected to these three items.

UPDATE #2: Paul Greaves has the answer! These "Siemens-Bock" style railroad insulators, rated at 3KV, were used to support overhead trolley power lines. Nora Coppo has a nice example of these in both green and white posted here: [id=140424870] and [id=138201279] I have another photo of these in use, I'll post later. Here it is: [id=165237286]