Thanalan - train tracks... what are they for?

[Sove92]

There's Nanawa Mines by the zone to north thanalan (yet there's no mining points there).

That would be because Nanawa Mines is actually after the zoneline, you go through the mines to enter North Thanalan, but the mines are skipped in gameplay (much like Coerthas Eastern Lowlands and Coerthas Central Lowlands), it was a playable open world dungeon in 1.0.