look the same time as the conventional trains, and that they would use one minute more than in 1982. Starting on 15 December, three of the services on the Østfold Line were extended to Gothenburg in Sweden. On 21 February 2007, a Class 73 derailed after hitting an avalanche between Hallingskeid and Myrdal on the Bergen Line. The accident raised questions about the class's abilities to handle hard snow, such as in avalanches. In particular, a DNV report from 1999 had shown that the train could act as a sled, lose contact with the tracks and slide on top of the snow. A former NSB employee who worked with route planning, stated that a locomotive-hauled train would be better suitable for such situations, because more of the weight is located at the front of the train, and it will therefore plow instead of slide. The National Rail Administration said that they took extra precautions for the Class 73 trains and that during snowfall they would run a snow-clearing unit ahead of all Class 73 runs. NSB stated that they would consider the possibility of reverting to conventional trains, but that unless new information could shed light on the situation, they would retain use of the Class 73 trains. 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. On 16 June 2011, a fire started in the snow tunnel at Hallingskeid Station on the Bergen Line. As the station is unmanned, there was no prior warning of the fire until the driver saw it