Orrick near Bric-a-Brac in U'dah:

"While on the subject, my sources give me to understand that a plan is in motion to lay a magitek railroad across the wilderness. Should this knowledge bring you in wealth in the future, remember to whom it is you owe your good fortune."

Not sure if this was added recently or not, as its been awhile since I talked to this particular NPC, but I don't recall him saying it before. Nice to see already something in the game referencing that railroad we've seen in concept art and those gameplay shots.