“Many of them have neck pain and some of them who have come in have symptoms of shock,” said Malin Lutz at Sahlgrenska University Hospital.
According to SOS Alarm the accident happened on Lisebergbanan, a ride built on a hillside at the park.
One of the wagons was stationary at the start point and passengers were in the process of climbing out when another wagon rammed into it.
According to a statement from Liseberg later on Saturday afternoon, a lock on the chain which pulls the wagons up the hill broke. The wagon then slid back down the incline into the start area.
“Obviously there was a considerable crash,” said Lasse Zagai, the duty manager at the park.
Lisebergbanan runs automatically and the operator who watches over the ride is unable to stop the wagons manually.
“Normally there are sensors which measure how the wagons move,” said Lasse Zagai.
Every wagon has an extra security device which should prevent it from sliding bacwards. But according to the park’s management, since the whole train was not yet up on the hill, it had not locked.
The Swedish Accident Investigation Board will carry out an inquiry into the incident, Gothenburg police announced. The ride will remain closed until the investigation is complete.
The injured people were taken to three different hospitals: Östra, Sahlgrenska and Mölndal, a police spokesman told TT.
The Lisebergbanan rollercoaster ride is over 1,500 metres long and five wagons operate at speeds of up to 80km per hour. Each wagon carries 22 people.
The ride opened in 1987 and this is the first accident of its kind.