Tsunami, M&Ds Scotland’s Theme Park, UK

Nine children and two adults were hospitalised after all five carriages on the Pinfari-manufactured coaster came off the tracks, plunging roughly 20 feet (6m) to the ground and hitting a child’s car ride, before coming to a rest upside down, leaving riders trapped. Source

Tsunam M&Ds Scotland's Theme Park Accident
Police with Health and Safety Executives investigate the incident.

Zippin Pippin, Bay Beach, Wisconsin, USA

One rider and two workers were injured when an occupied train failed to stop properly, hitting an empty train in the loading area, which in turn hit the workers. Source (with video report)

Zippin Pippin Bay Beach Wisconsin Accident
Fire truck at the scene of the incident.