She's using "homeland" like a repatriated soldier, I think.
Close. The word "Naichi" that Hoppo's using there was commonly used by Imperial-era Japanese to refer to Japan proper, as opposed to its colonies in mainland Asia and the surrounding islands. Nowadays the only places you're likely to hear it are certain parts of Hokkaidou and Okinawa.
We'll be riding this train...This is a train...!?
It's so long...!Outside's whooshing past...Huhuhu...
Trains are amazing huh...The homeland sure is an amazing place...Where did you learn such words...?Go by Train...!It's so fast...!