Following the discovery of cracks in February, DSB commissioned German Rail (DB) engineering consultancy subsidiary DB Systemtechnik to carry out an investigation into the causes and potential solutions to the problem.

The evaluation, which was published on the DSB website on July 8, shows that damage to axleboxes and primary dampers were the result of several factors, which DSB says will require further investigation.

DB Systemtechnik recommends fitting the vehicles with an optimised shock absorber and the wheelslip protection system should also be recalibrated to reduce tread damage. The report suggests testing wheelsets with higher tensile strength and the preparation of detailed maintenance instructions for axleboxes, together with a visual inspection every seven days. New calculations are also recommended to establish the true strength of the axleboxes, taking into account the actual damper force. This data can then be used to develop an optimised axlebox configuration.

DSB says it will now carry out tests on the basis of the report's recommendations, including running and braking technical investigations, residual stresss management and non-destructive testing of the damaged wheels, and development of detailed damages statistics.

Last month DSB announced it would launch a further study to ascertain whether the troubled fleet has a future, particularly in light of plans to electrify a much larger proportion of the Danish network than was envisaged when the trains were ordered in 2000.

"The final report supports the conclusions that were instrumental to DSB's decision to launch a new independent investigation into whether it is feasible and economically reasonable for the fleet to operate with a sufficiently high level of operational stability," says Mr Steen Schougaard Christensen, DSB's maintenance director. "The recommendations of DB Systemtechnik and our operating experience will feed into the overall assessment of whether it is worthwhile continuing with the development of the IC4 and IC2 trains, or whether to launch a Plan B."