Although trains of the Tozai Line, except for direct trains from the Keishin Line, currently run at 7.5-minute intervals, their interval when the line came into operation in 1997 was ten minutes, which was inconsistent with that of direct trains from the Keishin Line, and in 2000 the interval was changed to 7.5 minutes in order to make it consistent with the operation pattern of direct trains from the Keishin Line.
なお、京津線直通以外の東西線列車は現在7分半間隔の運転であるが、1997年の開通当初は10分間隔で京津線直通とパターンがずれていたのを解消するため、2000年に7分半間隔に増発して京津線直通とパターンを合わせたという経緯がある。