Ansaldo still has some literature about the Identra coils on their website (does this mean they still support it?)
The coils were in use until the early 2000s, I only remember seeing them on the St. Clair West short turns. Until the late 1980s-early 1990s service cuts there were more scheduled short turns, I also suspect they were used then.
Identra coils were also used for route selection on the CTA. I always thought that in the interlining period the TTC handled route selection was handed with punch tape machines, not the coils (which caused problems when the service on the ground didn't match the schedule).