Amtrak

The National Railroad Passengers Corporation, better known as Amtrak, is a trans continental railroad system that passes through most of the continental United States of America and parts of Canada.

The Lightning Thief
Percy Jackson, Annabeth Chase, and Grover Underwood take the system from Leeds Point, New Jersey to Denver, Colorado with a pit stop in St. Louis, Missouri.

The Tower of Nero
Apollo and Meg McCaffrey take Amtrak from Washington, D.C. to New York City.