Yea , thats some nice ideas guys. This is just being a little too dreamy but here is a idea that might never be in this game but here it goes.
As Cities gets bigger and gets provided with goods and passenger , they have certain wealth groups , and they demand ceratin things like , Cheapest travel for a little less fortunate populace(maybe passenger trains and huge ships and buses .Faster travel for rich populace (Airplanes and fast bullet trains.) and so forth on.
I think this will add great depth to the game and people selecting what and which transportation to select where , will make it more strategical , then just building a system from place A to place B.
I think this can be introduced because we already have wealth maps and stuff. and Things like Airplanes and faster trains can integrate well in the game through this.
What do u guys think?