御堂筋線
According to the original plan laid out for the Tanimachi Line in 1927, it was to follow Matsuyamachi-suji (to the west of Tanimachi-suji). It was also intended to interface directly with the Midōsuji Line directly at Umeda, similar to the cross-platform interchange between the Yotsubashi Line and the Midōsuji Line at . A second tunnel was dug at Umeda for this purpose, but the connection southwards was plagued by collapses and other accidents; as a result, the planned route was changed to the current one, stopping at Higashi-Umeda and then veering eastward. The tunnel at Umeda reserved for the Tanimachi Line ("Matsuyamachi Line") went unused for decades before finally being adapted for the southbound track of the Midōsuji Line in 1989, allowing for expanded platforms to cope with overcrowding.