Most of the older installs have been phased out in the past 7 to 8 years, good thing we have some photos to preserve these before they get replaced by boring modern equipment:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160808%2F5f412160446d23da088a3509f605b7c7.jpg&hash=876d8b356cfea77ddccbd48aa6812d39217d6f2b)
These signals are very old mast- supported 12" Eagle Flatbacks, installed waaay back in 1972, 44 years ago, two years closer to the 1920s then to today! I'm not sure if these are still up, due to to a recent PennDOT replacement program.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160808%2Ff65ab0e1f8528fc84cb52565915ae332.jpg&hash=839fad80b31d90b38e128c2aaa41202b458f5f7c)
A primitive set of CH Art Decos, probably installed around 1950, these are pretty old though. The only reason why these ancient artifacts are still here is because this are (Philadelphia Naval Base) is almost entirely abandoned
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160808%2F1c480ea772511506cb373a4b66a595b8.jpg&hash=c83d5743ad1b7a45f8bec5031b0708a62e5e2060)
We have a Generation 2 Durasig, probably installed in 1990-91, 25 years ago.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fuploads.tapatalk-cdn.com%2F20160808%2F6673acdcec8bd0f0518f94a9838617b1.jpg&hash=5b6a794ca9359291b3a356b4737c8ba654ee6169)
Another old '70s-era 12" Eagle Flatback mast-arm install, the Eagle Flatbacks are original while the 3M is slightly more modern.