When do Fastpass machines turn on?

[disneylover102]

When exactly do FP machines turn on? Is it right at 10 or is it earlier? How long of a line do EMH people make to get FP for Thunder Mountain?

 

[Karin1984]

They start at 10, first return time is 10:15 (?) and the majority of people during EMH have just ridden it. Most will go do other stuff and not join the FP line.
Now that it's open during EMH the morning dash for FP has really changed.