While there are no hard and fast rules to joyriding, there are some general parameters. The first is that is should involve something stolen; preferably the ride itself, but we'll also accept stolen cargo like a stuffed alligator or live great horned owl. Second, there should be some amount of freedom to the ride, i.e., you can go wherever you want. That freedom is part of what puts the "joy" in joyriding.
Which is why we're baffled by one woman's attempt to take a train for a joyride. Sure, the train would've been stolen, but those pesky tracks tend to limit your freedom of joyriding, no?