Ninja Coaster derails at Six Flags Magic Mountain theme park, injuring four people

A ROLLERCOASTER at a theme park in Califoia struck a tree branch and derailed today, injuring four people and leaving 20-30 people stuck six metres off the ground.

Local television station KTLA reported four people received minor injuries on the Ninja Coaster ride at Six Flags Magic Mountain just before 6pm on Monday evening local time (11am AEST) and up to 30 were stuck off the ground, a fire official said.

Los Angeles County Fire Department first responders were called to the scene just before 6pm, according to a supervisor with the department.

Twenty to 30 people were stuck about 20 feet (six metres) off the ride, fire Supervisor Ed Pittman said.

NBC Los Angeles tweeted the 25 riders were stranded after a tree branch fell on the roller coaster tracks. Crews used heavy equipment to extract the passengers.

Theme Park Adventure magazine tweeted: “News copters are overhead. Guests calm on train.”

All riders were eventually rescued by authorities by about 8.30pm.