The capacity of transportation in this section was once considered insufficient, and in the past certain trains, such as the express service 'Isokaze (train),' were split at Nagatoshi Station and ran via the Mine Line.
この区間は輸送力が低いとされ、かつては急行列車「いそかぜ(列車)」などのように長門市駅で分割し美祢線経由で運転されるものもあった。