We all know in a game it doesnt show you every single town that actually exists in its world ans the towns it shows are never the full real size, and its world is far larger in its reality then what it shows in you game, to the people it wouldn't take a 4 second walk to cross the world but months in the wilderness with no roads and monsters. Tzen was a Kingdom with its own monarchy before the game and you never see the trace of there castle.
You can already see the need for a train service. There was probably alot of small towns in the kingdom it connected that was destoryed or not shown in game. It may of connected the kingdom to others and the outside.