Well, as far as bad smells on train are concerned, I have experienced it here in Australia as well. And the reasons range from people eating smelly food, to people travelling with smelly food, to people coming after heavy smoking, to people smelling like stale piss... It can be any ethnicity, it's not limited to any single one.
And in Pakistan? I never travelled on a train in Pakistan my entire life. And most buses in Karachi are like overcrowded chicken coops. Buses in Lahore are much better. But all this information is rather dated now.