According to the revision of the time schedule made in January 2008, the number of trains was reduced for the first time since the line went directly into the subway, but such reduction was made only in the time zones other than the daytime and the 15-minute interval in the daytime remained unchanged.
なお、この2008年1月に行われたダイヤ改正では、地下鉄化後初の減便改正となり、日中の15分間隔である事は変わらず、昼間以外の時間帯で減便がなされた。