Under such circumstances, local trains were also equipped with air-conditioning, including the Yamanote Line, Chuo Line Rapid service and the Osaka Loop Line, followed by Keihanshin Local Line as the fourth with eleven trains consisting of seventy-seven newly built air-conditioned cars from January to March of 1974.
そんな中で緩行の冷房化が行われることとなり、山手線、中央線快速、大阪環状線に続く4番手として、1974年1～3月に京阪神緩行線に新製冷房車が11編成77両投入されることとなった。