These towers are the most stupid looking, ugly duckling towers I have ever seen. The pins for the M-3890 insulators are still mounted on all 3 spots on the tower and a U bolt goes over them fastened to the angle iron supporting the suspension insulators.

Note: the pins have no lead threads or any indication showing any other insulator being installed besides the angle iron suspension modification. I did find a discarded suspension string that dates from [19xx] (Suspension experts please let me know).