Eerste deel van de pers bericht, rondom de redenen van het ongeluk.
Sequence of Events
The Swedish Accident Investigation Authority’s investigation shows that the front axle on the first car of the train, where the wheels are attached, collapsed and fell off. This led to the train making severe sudden stops as the underside of the car hit various joints in the roller coaster track. Passengers were thrown forward with great force, causing the safety bar mounts to bend. The safety bars are designed and adapted for this type of attraction, but in the accident, the bars were subjected to forces five times greater than during an emergency break.
The Front Axle
The report indicates that the new front axle installed on Jetline in the spring of 2023 was improperly manufactured. It lacked an internal cross plate and had serious welding defects. This resulted in the front axle having insufficient strength and breaking. The manufacturing defects were on the inside of the front axle and were not detected in subsequent inspections.
The Order and the Manufacturing Drawings
This type of front axle is expected to last a long time. The original front axles had been on Jetline for over 30 years and were starting to wear out, which is why Gröna Lund ordered replacement parts in 2019. The order was placed with an experienced and proven Swedish supplier that Gröna Lund had worked with for over 15 years and who had previously manufactured other parts for Jetline. Manufacturing drawings from the original manufacturer of the trains were sent with the order, and an exact copy was ordered with post-production inspection of all weld seams. The supplier then subcontracted the order, something Gröna Lund was unaware of.
The original drawing can be interpreted in different ways regarding whether an internal cross plate should be used as support. The Swedish Accident Investigation Authority’s expert believes the drawing is unclear on this point, while experts consulted by Gröna Lund find the drawing clear and suitable as a manufacturing basis. The Swedish Accident Investigation Authority’s report shows that the subcontractor had uncertainties about how the welding should be performed and that these uncertainties were never discussed with their client or with Gröna Lund. This led to the absence of the critical internal cross plate. The report also shows that the original drawing was deviated from and there were serious welding defects on the inside. The welder who performed the work had no formal welding training and no valid welding certification.
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