One main theme is isolation. The signal man is alone in his post most of the time, cut off from the outside world. Another theme could be the supernatural. The strange apparitions he sees add an element of the unknown and the spooky to the story.
The themes in 'The Signal Man' short story are numerous. There is the theme of industrialization and its impact on individuals. The signal man's job is a product of the industrial age, and he is almost a slave to it. The story also has a theme of communication, or rather the lack of it. He tries to communicate the strange things he sees, but no one really believes him at first.
In 'the signal man short story', a significant theme is the power of perception. The signal man's perception of the apparitions and his attempts to make sense of them are central. There is also the theme of the industrial age and how it can be a desolate and isolating place. The railway setting, with its tunnels and tracks, represents this sense of a cold, mechanical world where the signal man is just a small part, yet he is haunted by things that seem beyond this ordinary world of trains and signals.
The primary character is the signal man. He's a lonely figure, working in isolation at his post. There are also some other minor characters like the narrator who interacts with the signal man and tries to understand his situation.
The main character is the signal man himself. He is the central figure around whom the whole story revolves.
The main plot is about a signal man who works in a lonely and rather eerie location. He experiences some strange and disturbing apparitions. These apparitions seem to be warnings of disasters that are about to occur on the railway line he is in charge of.
The main character is the signal man. There may be other minor characters like the people on the trains he is signaling for, but the story mainly revolves around the signal man.
There might be a character who is waiting for the signal. This could be a person in love waiting for a signal from their beloved. Or perhaps a spy waiting for a secret signal to start an important mission. The story could build around this character's anticipation and what they do when the signal finally arrives.
The moral of 'The Signal-Man' could be about the power of the supernatural or the psychological impact of fear. The signal man is haunted by apparitions which lead to his doom. It shows that we should not let our minds be consumed by unexplained and terrifying things, as it can cloud our judgment and lead to bad outcomes.
Another possibility is that there are multiple main characters in the story. For example, a group of astronauts might be the main characters if the signal is received while they are on a space mission. They would have to decide together how to respond to the signal, and their different personalities and backgrounds could create conflicts and cooperation within the group as they deal with this unexpected signal.
I'm not sure specifically as there could be many 'the signal' short stories. It might be about a mysterious signal received from outer space, perhaps dealing with the discovery and the attempts to decode it, and the implications it has on the characters in the story.
One common theme could be self - discovery. For example, in many stories, the man protagonist embarks on a journey, either physical or mental, and through the experiences he has, he discovers more about himself. He might learn about his strengths, weaknesses, or his true desires.