I have hooked up my latest version of autonomous railway junctions in a demo world. I have one station per continent (not Antarctica) and the player can select from one of hundreds of cities around the world.

This trip starts in N. America, goes to Europe, Asia and then back to N. America (using the nether to represent going East, crossing the Bering Strait into Alaska)

The train will automatically route to the destination in whichever book you last read.

demo here