BUMAX solves corrosion issues on wooden roller coaster 09 May 2019

The Balder roller coaster at the Liseberg amusement park in Gothenburg, Sweden, is said to be one of the best in Europe – but was in urgent need of a high strength and corrosion resistant screw solution following two failed fastener solutions.

The Balder roller coaster was opened in 2003 with 8.8/10.9 carbon steel screws that began corroding, rusting and braking after only a few years. Liseberg started replacing the carbon steel screws with A4 screws, but these were too weak and also started breaking.

A strong but flexible and fatigue resistant screw was needed to secure the roller coaster rails to the wooden frame, which expands, contracts and moves throughout the different seasons. Corrosion resistance was also necessary to deal with the impregnated wood, and the corrosive local environment caused by vehicle emissions from the adjacent E6/E20 highway and salt water from the nearby sea.

The Liseberg amusement park approached BUMAX for a solution, and 355mm long specially designed M10 BUMAX®88 screws were used to successively replace the existing carbon steel screws between 2009 and 2018.

One of the main reasons why BUMAX®88 was a success compared with the fasteners Liseberg had previously tested was its excellent fatigue resistance. Third party tests have shown that standard BUMAX®88 can withstand 10 million cycles at a preload stress of 400±55 MPa with no screw fracture. This compares with 0.4 million cycles before an A4-80 screw fractures. As of March 2019, no issues have been reported with the BUMAX®88 screws installed.

Cost savings
Before all the screws were replaced with BUMAX®88, fractured screws had to be replaced on an ad hoc basis, which resulted in ongoing costly maintenance and operational delays for the roller coaster.

Safety benefits
Roller coaster safety is paramount and BUMAX®88 ensures that the roller coaster continues to function safely. There is also now no need to replace screws on the roller coaster, which previously required potentially risky maintenance work at height for the Liseberg maintenance team.

Environmental benefits
Stainless steel is 100% recyclable and retains its original physical properties in the process. This recyclability reduces the use of virgin material and lifecycle carbon emissions.

Claire Aldridge Deputy Editor t: +44 (0) 1727 814 450

Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.

Claire prides herself on keeping readers well informed and up to date with the latest industry news.