Making this up... but...If there was a vehicle (like a car) that could straddle a block (or a specific block/shape) and not be able to drove off of it, then that would work. Then an enhancement would be "it can move forward without a player", so you could have it always driving... but i would assume on e it made it to the end of the chunk and entered one without players, it would stop moving. BUT it would be useful for mining/mines and traveling as you could ride in it and use it for storage.... if you built the track. But it would be cool to come a ross "useable track" in an RNG world that you could work with.
Additionally, if this existed ( vehicle or object with wheels that could stay on a track) it might make some interesting "traps": in a poi it could roll and fall and block your path, it could be used to fall on or block zeds (they break blocks, trap blocks, it freely rolls). It would also open up some "liveliness" to pois (like a roller coaster or carnival ride that actually works, ride it (or just stand on it... so you can shoot) and shoot zeds like an old "rail shooter" mini game.