Well, it's the man. He's the one on the train, so presumably all the action, thoughts, and experiences in the story are related to him. He could be an ordinary person with an ordinary life, but the train journey might bring out something unique about him, like his courage in a difficult situation or his kindness towards others on the train.
The main character is the man. He might be described in detail in the story, including his appearance, his personality traits, and his background. His actions and decisions on the train are likely to drive the plot forward, whether he's making a new friend, solving a problem, or just daydreaming during the ride.
As we don't know the details of this story, the main character is presumably the man on the train.
The main character is the 'train man' himself, but we don't know much more without further details about the story.
Obviously, the main character is the man in the train.
The main character is the old man. Since it's called the 'old man on a train story', he is likely to be at the center of the narrative. He is the one whose experiences, actions, and thoughts are probably being focused on during the train journey.
It depends on how the plot of the novel is structured. If the narrative mainly revolves around 'Train Man' and his experiences, relationships, and growth, then he is probably the main character. However, if there are multiple storylines with equal importance given to other characters, then he might not be the sole main character.
Not having read 'the man on the train short story', it's difficult to determine the main characters precisely. The man on the train is surely a central figure. There could be a mysterious stranger sitting next to him, who is also a main character and whose actions or words drive the plot forward. Additionally, there might be a family on the train that the man interacts with, and they play an important role in the story as well.
Since we don't know the specific 'man vs train story', it's hard to say for sure. But obviously, one of the main characters would be the man. And the train itself could be considered a kind of character in the sense that it has an impact on the man's situation.
The main character has to be the girl on the train. The entire story seems to revolve around her. Whether she's traveling alone or with someone, whether she's going on a short or long journey, she is the central figure in this 'the girl on the train 2013 story'.
Since I don't know the exact story, I can't say for sure. But it's likely the girl who is on the train in 2021 is the main character.
Since it's called the 'girl on the train story', the main character is most likely the girl. She is the central figure around whom the story presumably revolves.