Earlier today I caught an episode of the Jimmy Neutron cartoon on Nickelodeon. In it, Jimmy had brought Thomas Edison to the present, and the longer Edison was away from his own time, more and more electrically-operated machines either disappeared or stopped working. Jimmy's two friends were riding a roller coaster when the whole thing spontaneously lost power, and their car was stuck upside down (and when the power returned later, their car resumed its travel).
This threw me a bit, because roller coaster cars don't run on electricity; they mostly run on inertia. Cars are pulled to the top of certain hills by motors, but then gravity and momentum do the rest. There's no reason for the car to stop due to a lack of electricity, particularly not upside-down.
Sure, this is a cartoon about a time-travelling Thomas Edison and vanishing jukeboxes. Malfunctioning roller coasters are its least absurd element. But 'electricity is disappearing' was the conceit that was introduced, and then executed poorly. I remember Mark Waid doing a similar thing in his "Tower of Babel" arc in JLA. Ra's al Ghul had rendered the people of the world illiterate, which is certain to create some havoc. But one of the dangers shown was somebody jumping on the subway tracks when they couldn't read the "Danger: Third Rail is Deadly" sign. As if Ra's had made people not only illiterate, but forgetful and stupid. The sample scenario just didn't jive with the fantastic conceit.
On a related note, every so often one hears about a roller coaster getting stuck upside down. What *can* go wrong on a coaster to make that happen? This one apparently had a broken wheel assembly, but what other mechanical snafus that can cause such a problem?