Tokyu (Tokyo Kyuko, 'kyuko' means 'express') is not the longest private railway, but financially it is one of the most important compamny in Japan.Toyoko line connects two largest city in Japan... Tokyo(Shibuya) and Yokohama. The line runs through the most popular area as a living place,so the line is always crowded. From 2003, it runs through Minatomirai-line (MM21). Series 5050 and 9000 are used.東急東横線は、田園都市線と並んで東急電鉄の中核となる路線です。8000系・8590系が撤退し、東急車は5050系と9000系、日比谷線から直通する1000系に統一されました。