Along with my previous posts about double stacked insulators in service... here are some more modern brown insulators that are in a stacked arrangement like the gray OB's .This pole structure dates from around 1906 and once had M-3890's on it. Pieces of them were to be found around the structure. The insulators here are some sort of big brown four part multi's note that the left and top phases have both been damaged by flash overs and are now replaced by posts . this line is now running@34.5 kV but once ran @60kV. I would guess the pin insulators here are from the 1930's or early 40's . It is interesting to note that many if not most all of the pin types still in the air on these old structures have considerable flashover damage. VERY few pin types remain in service on these early lines. This tower structure is actually over 100 years old !