 Three days before scheduled services were to start , permission to use the trains had still not been granted by the Norwegian Railway Inspectorate . The inspectorate had a series of safety concerns , including follow @-@ up on the safety terms for the wheels and axles ; lack of documentation of the crew 's training ; denying NSB 's request to have fewer inspections and less maintenance on the trains ; lack of consideration of critical events deemed to have a high probability to occur but have a low consequence ; lack of a safety inspector for operations and maintenance ; and that the trains were so heavy that they would exceed the permitted axle load of the lines . Det Norske Veritas ( DNV ) warned against a possible weakness in the axles . NSB wanted to use an expert from Deutsche Bahn to perform the necessary tests , but limited availability of the expert resulted in the Norwegian National Rail Administration granting a half @-@ year delay of the inspections . 
