They were then introduced in 1966 to the Joban Line on which distances between stations are long, and where no drastic amendments were made, other than installing disk brakes, thanks to the study results obtained when they were introduced to the Keihin-Tohoku Line.
その後昭和41年度より更に駅間距離が長い常磐線に投入される事になるが、先に京浜東北線投入時の研究結果があったために、ディスクブレーキ付きにはしたものの、抜本的な性能に変化はなかった。