One tile off the coast

[teh DG]

A lot of tiles that's just not possible.

sorry I meant that when deciding where to place cities I only count the 4+ tiles (and usually you'll find these are the ones the city is working)

But [a harbour] will not net you the 50% railroad production bonus.

Yeah it does, it's not documented anywhere but you'll see it in the city screen and it is effective. But, it requires a harbour either in the capital or in another city that does have a railroad connection to the capital.

I've not tested but I assume if your harbour city is connected by rail to another, that one will also get the production bonus.

In short I think it follows the same rules as trade routes, just not counting roads.

 

[Ironmonger69]

In my current game as America (Huge map), I've conquered most of one continent, so I can see plenty of coast line. On Year 1993, and have yet to see any naval units from nations not on my continent, the lone exception a city state galley from far away that keeps tooling around my coast. The most I've seen any neighbor have afloat has been 1, plus an embarked settler. This is my first game, though, and on an easy setting, so that may change

 

[duxup]

I agree. I also have had to break myself of settling on the coast by default if at all possible. I've had good luck since then happily moving inland a tile away from the coast to pickup / expand to resources.