I rebooted the ioc using the green button in the center room and waited a few minutes -- didn't work.
I tried rebooting it again and waited a few minutes -- it didn't work.
I spoke with the tech on call about possible solutions (10 minutes). Just after I called MCC to request an ARM for a controlled access I tried bringing up the bogie contol GUI again and it worked... Maybe I just didn't wait long enough before?
Anyway, I tried everything _but_ releasing the brakes and the bogie
controller is now responding. Let's hope it works at 4am.