I lived 30 minutes from Six Flags over Mid-America just outside of St.Louis when I was in high school. Back in 1984 they introduced a short-lived standing rollercoaster called the Rail Blazer. The story was sensionalized locally and there were a few different versions of the incident.
A large woman and her husband was secured in the last car of the roller coaster and the ride was sent on its way. When it returned and the end of the run, there was only one passenger in that car. A woman was missing and her husband claimed she was flung from the car during one of the turns. She died from the fall and some unlucky teenager had the grusome task of locating the body among the trees below.
There are three accounts of what happened:
a) The lady was too big and could not be properly strapped in
b) The husband deliberately shoved her from the ride
c) The official report speculated that she fainted and slid out of her straps
At this point, the roller coaster was nicknamed the Hoosier Hurler. This ride was closed for a while and then converted into a sit-down ride called the River King. I never heard if any more details came of this. But around my high school, the saying went “The ride’s not over till the fat lady flings.”
The old UPI article is posted here on the NY Times site.