NOTE: THIS POST IS EDITED WITH NEWER INFORMATION; THE ORIGINAL POST FROM 7/5/09 FOLLOWS AT THE END. Thanks immensely to the insiders who have posted throughout the thread, allowing for a more complete picture of the accident (see in particular post #301).
Sequence of Events:
1. Monorail Pink leaves the TTC station on the EPCOT line. It intends to go a little distance on the line, then back up (going in reverse) onto a spur line and reconnect to the Express Line.
2. Monorail Purple, also on the EPCOT Line, is told to hold just outside (south) of the TTC. Purple is piloted by Austin Wuennenberg.
3. Monorail Pink (piloted by Alan Rubino) radios that it is ready for the switch.
4. Monorail Shop (the backstage facility that controls the switches) allegedly tells Monorail Central (the guy in charge out on the TTC platform) that the switch has been made. This turns out to not be correct. The switch hasn't been moved.
5. Monorail Pink allegedly gets the all-clear from Central, and starts to back up, thinking it's on the spur line. In reality, it's on the same line as before, and now heading toward Monorail Purple. Meanwhile, Monorail Purple is cleared by Central, so it proceeds towards the platform.
6. The anti-collision devices are turned off (both Pink and Purple are in MAPO-Override mode, which is required for the switch to occur), so Pink is not prevented from colliding with Purple just outside (south) the station. The NTSB initial report indicates that Purple stopped and tried to reverse course just prior to the collision, implying Wuenneberg (Purple) saw Rubino (Pink) coming. The driver of Monorail Purple, 21-year old Austin Wuennenberg, dies upon impact.
7. The two conjoined monorails are on an upward slope of track, and the collision kills power, so the trains coast back to the station and stop. At this point, the clickorlando.com video was taken, and the guests from Purple were evacuated.
Human Errors and Mistakes
a). The software and hardware appear to have functioned as designed, with no failures. The incident appears to be due to human error alone.
b). The Pink driver should have seen that he was on the wrong track. Various speculations to account for this lapse include distraction (cell phone?), fatigue, poor nighttime visibility, or window fogging (quite common here in Florida). On 7/9/09, this pilot was placed on paid leave by Disney (Disney says publicly that all suspensions are not punitive, but part of the investigation). In his statement on 7/10, Rubino says he was just doing what he was told by radio, something monorail pilots do multiple times every day.
c). The Purple driver appears to have attempted to back up at the last second, and so far appears to have done nothing wrong (in fact, he was paying attention). Why he did not release the override button and cause the system to force Pink to a stop automatically is not clear (perhaps in the heat of the moment, it did not occur to him).
d). The CMs on the platform have a killpack to kill beam power, and they should have used it when (if?) they saw Pink come back on the wrong track.
e). Monorail Shop people allegedly said the switch was moved when it was not. On 7/9/09, one person from Shop was suspended by Disney.
f). The platform Central Command coordinator is supposed to relay to Pink the all-clear. The scheduled person for this job allegedly went home sick.
g). The manager in charge (like the "Central" coordinator, but salaried) was apparently filling the duties of Monorail Central during the time of the incident, and rumored to be off-site at a Denny's restaurant when the accident occurred (pulling the strings by radio). It should be noted that the off-site rumor is one of the least substantiated reports so far, and must be taken with a grain of salt. A manager was suspended on 7/9/09.
a). Law enforcement and NTSB cleared the monorail for operation within a few days after testing rigorously for hardware malfunction. New sensors were installed on the switches.
b). Disney standard operating procedure was altered post-accident to require pilots to go through the switch "facing forward" (meaning they would have to switch to the back end of the train for leaving the station, and do the "backing up" part while going in the normal direction of the EPCOT line.) This takes longer and causes some guest inconvenience, but used to be standard procedure in the past, and is now being re-instituted.
There are still some points being debated, and this post will be updated as more information is obtained.
==========ORIGINAL POST FROM 7/5/09=================
"The monorails involved were the pink and purple trains, according to Local 6 in Orlando; pink was moving and hit purple, which was stationary."
It is absolutely not supposed to happen that monorails can come close to each other. The standard procedure is to test a new monorail joining the line by making it try to approach too closely to the one in front of it under controlled test conditions (it delays the monorails in front of and behind the new one undergoing tests). I've been on several such delayed monorails. If you get too close, the approaching monorail should get feedback from the ahead-one courtesy of a sensor, which tells the approaching monorail to kill the throttle (a so-called dead stick). The proximity sensors, if working right, are supposed to be 100% effective and completely prevent one car from hitting another.
These are apparently called the MAPO tests (I'm guessing due to the involvement in the early years by the Imagineering arm of MAPO, which manufactures the stuff WDI dreams up and was named for the MAry POppins movie).
So did they skip MAPO this time? Was it because it was so busy? The fourth of july is the busiest day of the year at WDW.
rumor time: I have seen Monorail Purple have problems first-hand in two of the last two times I went to the MK. One time resulted in kicking us all out of the MK station to use the boat while they towed purple. The other time required a restart of the electrical systems while we were at the TTC (also on the MK line). We actually made a verbal joke about purple becoming dangerous. Ouch.
Even though pink crashed (and the driver of pink is presumably the one who died), could it be because of a failed sensor on Purple? Did purple have an electrical outage that allowed Pink to not realize Purple was ahead?
Also: let's not forget visibility. The monorails have a headlight, of sorts, for running at nighttime, but it only illuminates a few yards ahead. If the sky is dark, you really wouldn't see hundreds of yards down the track.
Looking at the examiner.com photos of the crash, they seem to have a pic of the monorails smashed together in the TTC parking lot, and another photo of the same thing inside the station. Did the crash happen outside (just before) the TTC station coming from Epcot, while still in the parking lot, and they moved Purple (by tow? by its own power?) into the station after the crash to get people off? Or did it happen in the station first? How can both pictures be true?
EDIT: one later post in this thread claims that one train backed into the other, apparently oblivious to the presence of the stationary train in the station. This can only happen by holding down the MAPO override button, and requires specific managerial or CENTRAL approval. That theory holds the advantage that it explains why the drivers didn't see each other - one was backing into the other!