On my recent trip to IOA, I rode dueling dragons when there was no line at all. In total, I rode the ice 3 times and the fire 5 times. What I noticed on the Ice (and partially the fire, as its hard to see upsidedown), was that the trains must come within three feet of each other when fire is in the corkscrew, and the ice turns on to the brakes. Sometimes, the measure thing on the lift dosnt really work, giving one train a lead of the other. I noticed this "close call" was nearly doubled when the ice had a slight lead of the fire. I just wanted to get this out.