When I was a kid in San Francisco, I used to see a dozen or more poles on this 12kv transmission line, filled with Pyrex insulators. This four-mile line once supplied one of the city's main streetcar powerhouses. Then, one day, when I was about 10 or 11, all of the Pyrex pieces suddenly gave way, to Chance sky-yuck multis.
Over the years since, I have searched through thousands of old photos, to try to find an image clear enough, to identify the mysterious Pyrex insulators. Yet, all that I ever found, was a blurry pic in old trolley book (cropped enlargement shown on the lower right). So, I decided to try a CGI recreation, using my guess of Pyrex 401's (CD 325). The foreground pole proved to be a perfect test, as I knew that the porcelain pieces were Westinghouse M-2610b's. Looks like I found a match! Check out "View Original" to see the detail.