 In the first year of operation , the line had 60 @,@ 850 passengers , significantly over expectations . After the opening , there were five daily round trips . In 1939 , the extension of the longest tunnel started , because the nearby section was subject to landslides . It was completed by the German occupational forces during World War II , but not taken into use by the railway until 1945 because of the German military 's use of the tunnel as an ammunition depot . Because of the electric traction , the line was not affected by the lack of coal during World War II , and in 1945 it had 285 @,@ 900 passengers . After the end of the war , the number of daily round trips increased to seven , but this was reduced to six in the 1950s . In 1955 , a morning and evening coach service started between Granvin and Voss . It was further extended in 1968 , when it started corresponding with services on the Bergen Line . 
