The Seibu Tamako Line (西武多摩湖線, Seibu Tamako-sen) is a 9.2-kilometre (5.7 mi) single-track railway line in Tokyo, Japan, operated by the private railway operator Seibu Railway. The line is part of the Seibu Shinjuku group of railway lines that connects suburban areas of western Tokyo to Seibu and JR East main lines that extend to central Tokyo. The line is named after the (多摩湖, Tamako), a major reservoir supplying water to Tokyo, located close to the terminus of the line at Tamako. Since July 2008, recorded announcements on trains have been provided in English in addition to Japanese and, as part of Seibu Railway's ongoing refurbishment programme, signage and maps at stations are also bilingual.