Five people were injured when scenery from the coaster fell on the track causing the train to derail. Source
Accidents
Theme parks and roller coasters are statistically very, very, very safe. Out of the millions of people who ride the thousands of rides every year, there are only a small handful of incidents. You are statistically more likely to be involved in an accident driving to an amusement park than having one at a park. The rarity of accidents is one reason why the media report them, similar to plane crashes.
Every important element of a ride is inspected on a regular basis and every ride is tested every day without passengers before it opens. A ride might not open, or a safety system might activate, if there is an imperfection. For theme parks to operate, they must obtain insurance and one stipulation is their rides are frequently inspected and signed off by a strict Health & Safety governing body. Every theme park does what they can to prevent accidents because the negative press would be bad for business.
Having said all that, theme park accidents still happen…
Python Pit, Go Bananas, Chicago, Illinois, USA
A 3-year-old boy died after falling from the kiddie coaster. Source
Primeval Whirl, Disney’s Animal Kingdom, Florida, USA
A worker died when he was struck by a moving car while carrying out maintenance. Source
Spinning Coaster Maihime, Tokyo Dome City, Bunkyo, Japan
A 34-year-old man died when he was ejected from the coaster. Source
Thunder Dolphin, La Qua, Tokyo, Japan
A 9-year-old girl was injured when a 25cm long bolt fell from the coaster.
The Octopus, Adhari Park, Bahrain
A girl fell from the ride breaking her leg. Source
Pony Express, Knott’s Berry Farm, California, USA
Two trains collided causing 10 people to suffer minor injuries. Source
It’s A Small World, Disneyland Paris, France
A worker was trapped under a boat when the ride inadvertently started. He later died in hospital. Source
Tower of Terror, Disney’s California Adventure, USA
A 20-year-old man was hospitalized after falling 25 feet (7.6m) when he climbed over a barrier before losing his balance. Source
Terminal Velocity, Extreme World, Wisconsin, USA
A 12-year-old girl suffered brain swelling, multiple severe spinal and pelvic fractures and intestinal lacerations after falling about 100 feet to the ground from the SCAD (suspended catch air device) tower. An employee released the girl for the free fall without confirming that the safety net that was supposed to catch her was operational. Source