It is not because of the few thousand francs which would have to be spent to put a roof over the third-class carriages or to upholster the third-class seats that some company or other has open carriages with wooden benches ….What the company is trying to do is to prevent the passengers who can pay the second-class fare from travelling third class; it hits the poor, not because it wants to hurt them, but to frighten the rich . . . . And it is again for the same reason that the companies, having proved almost cruel to third-class passengers and mean to the second-class ones, become lavish in dealing with first-class passengers. Having refused the poor what is necessary, they give the rich what is superfluous.

—Jules Dupuit, On Toll and Transport. He would go on to say, observing the importance of sorting and price discrimination, “Travelers cannot be classed like merchandise by their appearance: they have to be allowed to sort themselves.”