just a thought how do we know the 60 old driver of the other monorail didn't have a seizure and blacked out. so if they have a heart attack who stops the monorails?
Under normal operation:
The top of the control stick that the pilots move forward and back to accellerate and brake has to be twisted 45 degrees in order for the train to operate. If it is released at any time, the console starts beeping loudly and the pilot has 3-4 seconds to re-engange the control stick. After that, the train automatically applies the emergency brakes and the train stops.
In addition, if the pilot runs past a hold-point (either by inattention or in the rare possibility that they become incapacitated in such a way that they're still engaging the throttle in the correct position), they'll get a red light on the console and the train will E-stop with a lot of beeping.
On the night on the accident, the driver of Pink was reversing the train while using the override button (under the direction of their manager). This override was necessary in order to move the train onto the spur beam. (it'd be a rather long explanation of the operation of the blocklight system to explain why this is necessary) While in override, the override button has to be pressed down with one hand while the throttle is operated by the other hand. (It's impossible to do it one-handed) While the override button is pressed, there is a very loud continuous beeping, and the train is limited to 15MPH.
So long story short, the driver of Pink did not have a medical problem the night of the accident. It was a confluence of a failure by someone in the Shop who didn't move the switch but indicated over the radio it had (at least by the reports I've read), the inattention of Pink's driver who didn't notice they weren't on the correct beam, and operating guidelines allowing this beam switch to be done while noone was in the control booth monitoring the position of the beam switches.
And to answer Turkey's question...
Only the Shop has the ability to kill the power to the entire monorail system.
In each station, there is a belt-pack worn by one of the platform CMs. That beltpack has the ability to kill the power to the beam(s) at and near the station it's assigned to.
At the time of night that the accident happened, I don't believe there was a CM assigned to the Concourse platform. There were no Guests heading to Epcot at that hour (perhaps just the random Guest leaving the MK who needed to get to their car in the Epcot lot), and the pilots of the trains stopping at the station were handling the train doors and station gates on their own. If there had been a CM on the Concourse platform wearing the beltpack, and they had noticed the impending collision, they would have (conceivably) been able to cut the power to the beam, which would have automatically E-stopped both trains. (It's yet another "if" that can be added into the reasons for the accident above, where if any one of them had/hadn't happened, the accident might've been avoided)
-Rob