The 155 Series School Trip Train, based on the then-current 153 Series, was introduced in 1959 as a vehicle exclusively for school trips for junior high school students during the postwar baby boom.
To avoid restrictions on the line's service area, all cars were designed with low roofs, resulting in a distinctive square body structure. Since
school trip trains prioritized interior space, narrow doors for boarding and alighting were used to prevent passengers from entering the train. These unique features included six-seater box seats on one side and four-seater box seats on the other, aisles offset from the centerline, and large removable tables in all box seats. The
bright vermilion and yellow school trip colors earned the train the nickname "Hinode-gata Densha" (Hinode-shaped Train) after the train's name.