 The tunnel is long with a cross-section, making it the longest tunnel in Norway when it opened, and the second longest since the opening of the Lærdal road tunnel.It allows speeds of , with a slope of 0.2–0.4% slanting upwards towards Lillestrøm.This provides a natural updraft in the direction of Lillestrøm, but a horizontal ventilation system was needed to work in the opposite direction.