Sun West Line is an automobile-carrying train created by Apollo. He tells Percy Jackson, Grover Underwood, Thalia Grace, Bianco DiAngelo and Zoë Nightshade to use it to go west.
Percy Jackson and the Olympians
The Titan's Curse
After defeating the Nemean Lion and losing their followers by taking a train, Percy, Grover, Thalia, and Zoë reached the end of the line with nowhere else to go. They approached a homeless man who is warming his hands in a fire in a drum can. He suggested they go on a train that was moving along, which turns out to be the Sun West Line. After they got on the train, the homeless guy disappeared. The homeless guy appeared again later and talked to Percy, where it was revealed that he was actually Apollo (disguised as a mortal called Fred). It was on this train that Percy had the dream that explained the past of his sword Anaklusmos.