All Aboard

All Aboard is a main quest $$.

Detailed walkthrough
The Sole Survivor will receive a new radio broadcast on their Pip-Boy after reaching level 30. After listening to it, a new location will appear on the map: the Nuka-World Transit Center.

A team of Gunners will be waiting here, with Commander Kaylor briefing them. Once they are dealt with, head inside the transit center. A seemingly injured man, called Harvey, will be sitting on the ground, claiming raiders took his family to Nuka-World. Offering to use a stimpak on him will present multiple hard speech checks which, if passed, will cause him to admit that the raiders are using him as bait to lure people to Nuka-World. He will give out the password to the terminal, regardless of what speech options are used. Once power is restored to the monorail, use it to leave the Transit Center and travel to Nuka-World. Once the monorail is taken, there is no turning back.

After a brief ride, the pre-recorded tour guide will be interrupted by Porter Gage, who will tell the Sole Survivor to survive the approaching deathtrap and find him.