 NSB assured passengers that the trains were more capable than their reputation , and that they would continue to be used on the Bergen Line . If an alternative was needed , NSB stated that they would have to use El 18 locomotives in combination with B5 carriages . However , the carriages were at the time being used on regional rush @-@ hour trains around Oslo , were in need of renovation and did not offer the facilities required by intercity travelers . In October , NSB stated that they planned to withdraw Class 73 from service on the Bergen Line , because the use of multiple units was not flexible enough . With locomotive @-@ hauled trains , it was possible for the company to add or remove just a single carriage , but with multiple units , it was necessary to double the capacity if a single unit was insufficient . While originally planned to be introduced in 2008 , delays in the upgrades delayed the delivery of the carriages beyond 2010 . 
