From Following the Equator:
January 30. What a spectacle the railway station was, at train-time! It was a very large station, yet when we arrived it seemed as if the whole world was present—half of it inside, the other half outside, and both halves, bearing mountainous head-loads of bedding and other freight, trying simultaneously to pass each other, in opposing floods, in one narrow door. These opposing floods were patient, gentle, long-suffering natives, with whites scattered among them at rare intervals; and wherever a white man’s native servant appeared, that native seemed to have put aside his natural gentleness for the time and invested himself with the white man’s privilege of making a way for himself by promptly shoving all intervening black things out of it. In these exhibitions of authority Satan was scandalous. He was probably a Thug in one of his former incarnations.Lest anyone miss this, the "white man's privilege" that Twain refers to is the privilege of thinking you're better than everyone else. Twain is not validating the concept.