 On 23 June , Quale stated that the inspectorate should never have approved the trains . He stated that the Sørland Line was extreme in Europe in the number of curves , and that this gave increased stress on the axles . The tests which were used to approve the trains had been done on the Dovre Line and with a Class 71 set equipped with tilting technology , a class which weighs less than Class 73 . He further stated that NSB had controlled only part of the axle and that if proper tests had been made , the fatigue would have been discovered . NSB stated that they had tested the trains on a section of the Dovre Line they considered to be more curvy than the most curvy parts of the Sørland Line . There was also a misunderstanding in the approval , as NSB had said to DNV that the tests on the Dovre Line were not to be considered representative for the Sørland Line , while the inspectorate had the impression that DNV had approved the tests also for the Sørland Line . NSB stated that all tests would be done again before the trains were put back into service . 
