The Sunset Limited
The Sunset Limited is the name of the train station the white professor wanted to use as his suicide spot. This station becomes the edge of the world and symbol of the end of suffering to him. Such a place could be seen as a symbolic representation of life where travelers with different goals and different ways of life travel towards the same destination.
Language
Not only are the two only characters of the play explicitly racially characterized with colors of their skin, but the language itself also poses a motif for this characterization. The language of the white professor is embedded with eloquence and metaphors, while the language of the black believer arguably shows a lack of formal education in comparison.