Ok, currently having a train route alone would be rather bad for certain area's.
Take Australia as an example. There's great travel across the country, but yet, we cannot link to any other countries.\
That doesn't help.
Therefore, I propose bringing in Ships to the equation, as an example.
Or like many others have considered, brining trains into the game.
However, why would we need trains, considering you would be limited to a small region, and not worldwide travel.
