The rapid trains had been managed with three-car trains on all the sections for the first year since when they were in full-scale service during March 1989, but they were changed to four-car trains on all sections from March 1990 because of heavy congestion.
快速列車は本格運転を始めた1989年3月から最初の1年間は全区間3両編成で運転されていたが、混雑が非常に激しいことから1990年3月から全区間4両編成に変更された。