Today at COSI/Toledo, Robin Innes reported that the lift speed should be about 11 ft/sec. That's roughly 7.5 mph. A back-of-the-envelope calculation says that for a 310-foot lift hill at 45 degrees, that's about 438 feet of track. At 11 ft/sec,. that would be almost 40 seconds to the top.
Ride time on Millennium Force is supposed to be 2:45 or so; I am guessing 2:42 to match the rest of the rides in the park ( :) ). That means a dispatch interval of about 70 seconds. To do that, the lift pusher would have to reset in under 30 seconds. To do that, it would have to make the return trip at better than 14 ft/sec, or about 10 mph.
For comparison, it takes 70 seconds to get from the station to the top of Magnum's lift hill, which is why that lift hill is almost never quiet for more than about fifteen seconds at a time.
--Dave Althoff, Jr.