While the OBA does function on all 5 trains, sometimes throughout the day the OBA on a particular train will develop SYNCing issues. The operators will reset the trains a few times and then eventually will just leave the OBA off if the SYNC issues continue. My recommendation is to ride early (Before noon) to ensure you get a train with functioning OBA.
I found this pretty cool time lapse video of how a traveling Ferris Wheel is assembled and a few other videos of fair rides being assembled. The nerd in me is happy.
https://www.youtube.com/watch?v=a1g_XB1mb5k
Couldn't find a "Traveling Fair" type thread and didn't want to create one just for this.