Road/railroad connection

[yanner39]

I can't find the info on this but when building a road for a trade route, does the road have to be from the city center tile to the 2nd city center tile or does the road simple have to be from cultural border to cultural border?

This could be important in trying to save road costs and improving only the less number of tiles possible with a road.

 

[Rathelon]

It has to connect to the city center tile. One exception would be the Iroquois, for whom forests within their borders act as roads, so they could have less actual roads built just to cover the non-forested hexes.

 

[Jamuka]

It has to connect the city centers.

 

[Moon Pine]

From one of the adjusted tiles of the city to one of the adjusted tiles of your capital.
Not must be in you cultural territory.
If a city connects to a city that connected with capital, it's also considered as connected.
If both a city and your capital have harbors, the city is considered as connected.