Shabdbhedi Express: गति इसकी शब्दों को भेदती है, पूरब को पूर्वांचल से जोड़ती है - Dr. Abhishek Rai

Your argument does valid in above case becauseIR taking more money from Passengers to give comfort that's why There is fare difference in 1 AC, 2AC,3AC, SL & Gen. Fare of Gen is less than other class because IR only giving Transport who paying fare for Gen Class.
BTW, in Above case, no one will agree that, in 2AC you will assume that there will be rats in coach.

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