I think the point is that these don't actually work in-game.people have already built recreations of the boomerang. its a pretty common ride and fairly easy to recreate using the coaster builder. if you are having trouble or would like to see a specific theme matching that ride, I'm sure you will see them become widely available once blueprint sharing is released in the next alpha. the one at my local park is pretty much the same exact boomerang, but I think the colors are different.
here ya go - https://www.reddit.com/r/PlanetCoaster/comments/4oc4z5/attempt_at_a_boomerang/
and/or this one - https://www.youtube.com/watch?v=8lnc3awGFmw