From 10 September 2012, 10-car 5050-4000 series sets entered revenue service on the Tobu Tojo Line, with inter-running through to the Tokyo Metro Fukutoshin Line.
From 10 September 2012, 10-car 5050-4000 series sets entered revenue service on the Tobu Tojo Line, with inter-running through to the Tokyo Metro Fukutoshin Line.