[1] On July 15, 2018, A Train To Autumn released a single titled "A Watercolor of a Rainy Day" which featured a male-female duet.
[4] In 2019, the group were officially introduced with the released of "Farewell Again"'s (다시 이별) showcase held at the Ilchi Art Hall on February 25.
[8][9] In 2020, The group's profile was removed from the Cube Entertainment website, confirming their disbandment.
[10] The members were mainly selected through blind vocal audition, except Soo-bin.
[11] The judges of the audition were led by Park Choong-min, the chairman of Cube Entertainment, professors of Howon University and more.