After the Ibaragi-Osaka section became a quadruple-track section, two tracks on the side became exclusive for urban electric trains (administered by the Railway Bureau) while two tracks on the outer side became exclusive for long distance trains (administered by the head office) - when the section was double-track section, local trains ran on the outer track and express trains ran on the outer track.
茨木～大阪間の旅客線の複々線化に伴い、従来の緩行外側線、急行内側線の運転形態から、内側線を電車線（鉄道管理局管理）、外側線を列車線（本社管理）とした。