Here's a video I found showing one of those SOX crosswalk signs being relamped with a pair of new 135w lamps. You also get a sense of the size of one of these signs as well as the internal layout.

Interestingly the ballasts are just hanging in the open inside the sign. I believe I saw a older version that used F-Can ballasts.

This video is pretty fascinating. I think this is the first time I’ve ever seen someone not only repairing one of these but getting up close and personal and how they service them.

After hearing about these signs getting retrofitted, I’m actually shocked to see they still relamped these with the proper SOX lamps. Perhaps they had stocked up or just clearing out their inventory.