COASTER COLLISION. 20 Injured in Swedish Roller Coaster Crash.

Two roller coaster trains collided at Sweden's largest amusement park Saturday, injuring about 20 people, police said.

It was unclear what caused the accident at the Liseberg amusement park in Goteborg, Sweden's second largest city located on the country's southwestern coast.

I'll do some more research on this story and report back. There are still some roller coasters in Sweden that have a brakeman controlling the train. Modern control systems sometimes prevent one train from being released to the chain lift while there is another train somewhere between the lift and the brake run.