[2] Passenger accommodation consists of rotating pairs of seats that can be arranged in longitudinal configuration for regular daytime services or in transverse forward-facing configuration for reserved-seat evening commuter services from Shinjuku in Tokyo to Keio Hachioji and Hashimoto.

[4] LED lighting is used in the interiors, and pairs of LCD passenger information screens are provided both above the doorways and suspended from the ceilings.

[5] Between April and May 2017, Keio held a public poll to choose the brand name for the new reserved-seat services starting in spring 2018.

[6] The fleet of five ten-car 5000 series trainsets was built by Japan Transport Engineering Company ("J-TREC") at a total cost of approximately JPY10 billion.

[4][5] The first trainset was delivered to Wakabadai Depot from the J-TREC factory in Yokohama in late June 2017,[7] and unveiled to the media on 19 July 2017.

[10] Reserved-seat Keio Liner services from Shinjuku Station commenced on 22 February 2018.