I have asked the question and haven't heard back yet, but I expect to see the new system at St Clair W to start showing up at various locations around 2025 once the existing fleet is gone. This will mean either the Witt, PCC's and any existing cars will be converted to pans or put on display somewhere, unless there are a few lines they can run with poles.
I have no idea why ppl are getting so upset when someone post x cars are on 501 when it can be y cars based on the time of day. So what if 10 cars were out at 9 am and 18 at noon. The schedule calls for cars to be roll out at various times and not everyone will be a Flexity at those times. Same goes from weekend to weekend. In fact, I knew 4511 was going to enter service today that I saw it still sitting in the yard at 6:30 am today, while someone else saw hours later still there until I saw it on 510 over 4 hours later than the first time. Normally, cars go into service before 7 am for weekdays and have been up to 8 am on the weekend. In the end, it was a later roll out today.
So what if the car was late going into service, let alone today, its in service bottom line. Even if it went into service like I said earlier this week, it in service sooner than most cars (11 days), especially 4408 that will be in service by this Friday if no problem surface, 31 days after arrival.
The same goes for number of cars system wide. Cars have to be maintain to the point some need more time than other, as well crews on hand to drive them and maintain them. Weekends will see less of these people.
One thing I will say to new poster, do some reading of the threads to see if your answer is there in the first place and it could be found 1-20 pages back before asking questions.