Kim Min-gi supposedly wrote the song in his senior year in high school. The story has it that one of his friends died in an accident on a high school camping trip, and he had to go visit the friend's parents to give them the bad news. He must have had a lot on his mind during the train ride, with the constant chugging of the wheels filled the air, which is probably what led to "Will the wheels of a train answer him".
Befitting the sad situation, the song evokes the heavy subject of life and death in the first verse, and that of the truth in the second. Was the accident of such a nature as to raise the question of truth? We don't know for sure, but the somber tone and enigmatic lyrics suggest such subjects. Whatever the author meant to say, it is a song that makes you think about how powerless and vulnerable we are, how precarious life is and how it can sometimes end tragically completely out of anyone's control.