10 September 2012, 10-car 5050-4000 series sets entered revenue service on the Yurakucho Line, with inter-running through to the Tobu Tojo Line. Future developments In 2021, plans were announced to branch the Yurakucho line at Toyosu Station, traveling north for connecting with on the Tozai line and Sumiyoshi Station on the Shinjuku Line and Hanzomon Line. An additional two stations (Edagawa and Sengoku) would also be added in the Koto Ward serving the Sengoku and Toyo districts. Tentative names for the new stations were determined in August 2022. The branch line (nicknamed the Toyozumi Line according to official city documents) is intended to aid in redevelopment efforts in Koto Ward. As of 28 January 2022 the expected cost of construction is ¥269 billion (2021) . The branch line is expected to be in service in the mid-2030s. A branch line from Toyosu Station has been planned since the early 1980s, heading north via Kameari Station (on the Jōban Line) to Noda in northwest Chiba Prefecture. References Shaw, Dennis and Morioka, Hisashi, "Tokyo Subways", published 1992 by Hoikusha Publishing External links Tokyo Metro website Lines of Tokyo Metro Railway lines in Tokyo Rail transport in Saitama Prefecture Tokyo Metro Yurakucho Line Railway lines opened in 1974 1067 mm gauge railways in Japan 1974 establishments in Japan