The Nuka-Express was created to quickly bring visitors to and from Nuka-World. Trains running every 15 minutes transported visitors from the Nuka-World transit center near Boston to the Nuka-World station.
The Nuka-Express is used as the beginning of the Gauntlet, an inescapable torture maze built by the Nuka-World raiders for their entertainment. Victims are lured into the Nuka-Express by Harvey, and essentially deliver themselves to their own death in the gauntlet.
The Nuka-Express monorail cars share similarities with the Boston subway cars, but repainted in a red Nuka-World livery and shortened considerably, along with some minor alterations to the body. Only the first car of the two is able to be entered, with the controls for the train located in the driver's cabin.