The 2023 Jetline roller coaster accident occurred on 25 June 2023 at Gröna Lund in Stockholm, Sweden, when a train on the Jetline roller coaster partially derailed, ejecting three riders and killing one. Nine riders were injured in total.
An investigation by the Swedish Accident Investigation Authority (SHK) concluded that a replacement front control arm, ordered by Gröna Lund in 2019 and manufactured by a subcontractor that lacked proper certification contained significant weld defects that reduced its strength. When operating, Jetline's forces exceeded the weakened arm's capacity, and the arm fractured and detached. This caused the front car to strike the track. The resulting forces bent the lap bar restraints of several passengers, causing them to be ejected or injured. SHK identified broader systemic failures at the park in overseeing the creation of the parts.
Following the accident, Jetline was permanently closed and later demolished. In November 2025, the park and two subcontractors were brought to a trial. Gröna Lund was later convicted and fined .
Jetline was a steel roller coaster at Gröna Lund in Stockholm, Sweden. Jetline was manufactured by defunct German manufacturer Schwarzkopf, and its trains were built by Zierer. It operated from to . It did not reopen after the incident and was eventually demolished.
On , at 11:36 am, train E, carrying eleven riders, derailed after travelling close to its third rise. The control arm (wheel-carrying support arm) on the very front of the train suffered a structural failure, becoming detached, resulting in the underside of the carriage striking the track joints at several points before coming to rest after travelling approximately one-third of the track. The resultant deceleration forces caused the eleven passengers on board to be thrown against the individual lap bars, some of which bent under the imposed dynamic load to such an extent that three passengers were ejected from the ride, one of whom was killed. In total, nine riders were injured.
Jetline's ride operators witnessed the incident from the ride's station and immediately called Gröna Lund's maintenance team. Several technicians responded to the roller coaster. At the same time, visitors to Gröna Lund had also seen the incident. Some visitors entered the restricted area to assist before emergency personnel arrived.
The first emergency call was placed at 11:38 a.m. and emergency responders were dispatched. The first resources from the Greater Stockholm Fire Brigade arrived at 11:45 with more arriving shortly thereafter. The rescue operation began immediately. The incident commander ordered the evacuation of the park, which was done ten minutes later with the assistance of Gröna Lund staff.
Upon obtaining a ladder truck, rescue personnel attempted to reach a person who was stuck on a support beam. After the rider was brought down, the truck was moved again to reach the passengers in the train. The technicians secured the train to the track and assisted firefighters in opening up the lap bars to release passengers. Medical personnel received injured riders after they were brought down from the ladder.
One of the ejected riders was declared dead on scene, following resuscitation efforts. Another ejected rider was initially treated on site and was later transported to a hospital by an ambulance. All passengers were evacuated from the train just over an hour after the incident.
Passengers in the other two trains that were running that day were evacuated by Gröna Lund staff and safely exited the ride. The rescue operation concluded at 2:52 p.m. The Swedish Police Authority closed off the area and later on prohibited operations of the ride.
The accident was investigated by the Swedish Accident Investigation Authority (SHK) with assistance from Elements Materials Technology AB and the KTH Royal Institute of Technology. The investigation began on . On , SHK published the accident report, concluding the investigation.
During the annual teardown of train B in , cracks were discovered in its front control arm. The wear on the control arm was deemed too great to repair. Because of this, it was decided that the front control arm for all trains would be replaced.
Gröna Lund placed an order for 5 control arms with Mekosmos AB, providing copies of the original drawings. The park expected the welds to undergo magnetic particle testing, but did not specify any additional manufacturing requirements. Mekosmos subcontracted the welding to Göteborgs Mekaniska Werkstad AB (GMW) without informing Gröna Lund. GMW purchased the materials needed and performed fabrication and internal checks. According to the welder, there was uncertainty about whether a backing bar was required. The question was referred to the employee managing the order at GMW, who determined that no backing bar was needed. No further verification of this interpretation was carried out. The welder did not hold a valid qualification certificate, although he had extensive practical experience.
The five front control arms were completed in and sent for magnetic particle inspection, which did not detect any defects. They were delivered to Gröna Lund in early spring of 2020. One of the arms was identified as damaged during manufacturing and set aside for scrapping, though it remained in storage. The remaining arms were installed on the trains. SHK concluded that the control arm that failed during the accident was one of the components manufactured from this order.
SHK determined that the component that failed was a front control arm manufactured as part of the replacement order. The arm deviated from the original Schwarzkopf design because it had been welded without a backing bar, and several of its welds contained significant defects. These deficiencies resulted in substantially reduced structural strength.
During the ride cycle in question, the operational forces exceeded the weakened arm's capacity, causing the welds to fail and the control arm to fracture. This failure led to the partial derailment of the front car, initiating the sequence of events that caused the fatal accident.
The lap bars were designed in accordance with standards that existed when they were built and no defects were found with the lap bars. When passengers were thrown forward, they generated force that the lap bars were not designed for. This caused the lap bars to bend, some of which bent enough to be entirely open. Only one lap bar did not bend at all. The lap bars being bent out of their secure position caused three riders to be ejected from the train. Testing showed that the restraints secured riders properly during normal operations and emergency stops. According to SHK, it is likely the restraints were not designed with anticipation that riders would experience that amount of force.
On , Gröna Lund announced that Jetline would close permanently. The ride was later demolished.
The accident drew attention to the challenges of manufacturing replacement components for rides whose original manufacturers no longer exist. SHK's findings identified deficiencies in ordering, documentation, subcontracting oversight, and quality assurance. As a result of this accident, the International Association of Amusement Parks and Attractions (IAAPA) did a case study of the incident that almost 100 members attended. IAAPA stated that the case study informed efforts to improve standards for replacement parts on rides from defunct manufacturers.
After the incident, Gröna Lund implemented several changes, including a new verification plan for the ordering process of replacement parts, updated ordering and installation procedures, and enhanced verification procedures for suppliers. Gröna Lund also implemented new and updated procedures regarding documentation.
Following the investigation, SHK issued a series of safety recommendations in its final report to four organizations.
After the incident, police launched a criminal investigation into the accident with possible charges of involuntary manslaughter, causing bodily harm and danger to others.
In early , the criminal trial began against Gröna Lund, Mekosmos AB, and the now-defunct GMW. The companies were charged with gross negligence causing death, gross negligence causing bodily harm, and causing danger to others. Prosecutors sought from Gröna Lund and from each subcontractor.
On , Gröna Lund was sentenced by the Stockholm District Court and fined . GMW was fined , while Mekosmos was acquitted.