209 series

The 209 series (209系) is an electric multiple unit (EMU) commuter train type operated by East Japan Railway Company (JR East) in the Tokyo area of Japan since 1993. The series was introduced in 1992 for experimental operations (as the 901 series) and in 1993 for commercial operations to replace the aging 103 series stock on the Keihin–Tōhoku and Negishi lines. The concept of the 209 series was to create a lower-cost, limited lifespan train (approximately 15 years) that would be replaced rather than rebuilt when they reached the end of their operational lives. The 209 series was the first of the "new series trains" (新系列電車, Shin-keiretsu densha), and served as the basis for the E501, E217, 701, and E127 series rolling stock, as well as the succeeding E231 series stock, which in turn became the blueprint for successive trains developed by JR East and other railway companies in Japan.