In the middle-end part of the movie Hugo, there is a train incident (symbolizing the 1895 Montparnasse Train Wreck) in the station. It seems pretty strange that the train incident is included in the movie, which happened at a different time than in the setting of the Hugo movie itself.
What is Scorsese trying to portray by including the incident inside the Hugo movie?
The train wreck is part of Hugo's dream. He has recently shown the drawing the automaton created to Méliès, who, in a state of sudden emotion, ejected Hugo from his home.
Hugo has felt that there is a part of his father's life which he can only access through repairing and understanding the origin of the automaton, and this rejection has left him reeling. This hurts all the more because even though Méliès is gruff with him, he has accepted Hugo as an apprentice, and is the closest thing Hugo has to a father figure.
He dreams of a train wreck, happening as he's attempting to retrieve the key from the track - the key that might give him a connection with his father, or perhaps more importantly access to a new father. The train wreck symbolizes that everything he's worked to resolve the mystery is crashing down, and in fact it is the key that makes him human. Without it he feels he has no place in society, and no right to happiness, as he's seen so many other orphans suffer at the hands of the stationmaster.
The reason it is that specific crash is that it originally occurred at that station, and so Hugo would have been familiar with the story, and probably have seen pictures of it. There doesn't seem to be anything particularly relevant about that accident and the film or Hugo, just that it occurred at the station the film is set in.
Is the train crash not a symbolic reference to the first movie that Méliès sees in the fair ground of a train arriving at a station? People are so startled by the train approaching the camera that they think it is going to crash into them. Méliès, at that time a magician, is so intrigued by the ability of the movies to 'trick' the eye that he gives up magic and moves into film making. It is only later that he discovers that film is also a fantastic storytelling medium.
The train is thus a symbol of the power of film to both 'trick' the eye and to tell a story. The two themes that Méliès is most intrigued by in his own film making. And by extension I assume Scorsese too.
I think that it means that Hugo's life is now complete with the key as he thinks but the train wreck happens because he doesn't know what to do as George's Mėlies still dislikes him though he is a bit kind to him. The dream represents the feelings of Hugo Cabret.
