One four-car set was modified from set 4009 into a tourist train called the for use on services operating between Seibu Shinjuku and Ikebukuro in Tokyo and Seibu Chichibu and Hon-Kawagoe in Saitama Prefecture, entering service from 17 April 2016. The interior and exterior design of the train was overseen by architect
Kengo Kuma. The automated on-board passenger announcements in Japanese use the voice of TV presenter , and the melody chimes accompanying the announcements were created by musician
Minoru Mukaiya, who was formerly the keyboard player in the group
Casiopea. File:Seibu 4000 series 52 Seats of Happiness car 1 4009 Bushi Station 20160806.jpg|Car 4009 (car 1) with spring motif File:Seibu 4000 series 52 Seats of Happiness car 2 4109 Bushi Station 20160806.jpg|Car 4109 (car 2) with summer motif File:Seibu 4000 series 52 Seats of Happiness car 3 4110 Bushi Station 20160806.jpg|Car 4110 (car 3) with autumn motif File:Seibu 4000 series 52 Seats of Happiness car 4 4010 Bushi Station 20160806.jpg|Car 4010 (car 4) with winter motif ==Special liveries==