Published: August 11, 2014 at 1:53 PM
It wasn't a shut-down in the purest sense of the word, the coaster valleyed. I was not in the park yesterday (almost went though), but have ridden Joker's Jinx many many times. There are no trims or other brakes on the coaster once you pass through the launch tunnel (unlike clones Flight of Fear (KD and KI) and Poltergeist (SFFT) that have MCBRs before entering the heart of the spaghetti bowl), there's nothing to slow the train until it reaches the final break run.
What likely happened (and this is pure speculation based on the reports and images) is that the train accelerated to the programed speed, and for whatever reason did not achieve that speed. Either there was a "shut down" at the end of the launch that caused the train to slow at the end of the launch track, or a set of LIMS malfunctioned that caused the train to not reach the optimal speed.
Where the train valleyed (after the cobra roll but before where the MCBRs are located on other clones of the coaster) would seem to indicate that it didn't have quite enough speed to get through the course, but too much speed to roll back onto the launch track (at ground level).
This incident reminds me a bit of the famous Top Thrill Dragster incident where a train got stuck at the very top of the tower and stalled on the apex. Cedar Point dispatched maintenance to the top to push the train over the hill, but in this case, the train was on a section of track that is not accessible except using bucket trucks.
It's an unfortunate incident, but it seemed to have been handled well by the park, and an occurrence that is probably close to 1 in a million.