I also didn't know Brampton had gumballs orignally. Now I wonder what the S arms in Thornhill used to have. I still see some remote ballasts in that area so my guess had been MV clamshells.
Speaking of clamshells, a lot of North York and Scarborough used to have clamshells or OV-25 remotes on S arms back in the MV days. They replaced the arms and installed OV-25s/125s during the HPS changeout.
I wonder if all the s arms were originally gumball or clamshell. Bramalea has lots of S arms still in this area. (westinghouse) OV-15, R37, R47, OVZ, and AE 115. Spadina also has some s arms by the gardiner
Speaking of clamshells, a lot of North York and Scarborough used to have clamshells or OV-25 remotes on S arms back in the MV days. They replaced the arms and installed OV-25s/125s during the HPS changeout.