The reasons were as follows: the increased number of trains in the Kintetsu Railway as well as the Keihan Electric Railway, the increased voltage to 1500V on the Kintetsu Kyoto Line (in 1969), and the difference facilitated by the ATS systems.
近鉄・京阪の列車本数の増加・近鉄京都線の1500V昇圧化（1969年実施）・ATSのシステムの違いなどのため。