It appears these were sold in the 1950s and 60s.
Photo of real ones.
Youtube video which shows a few shots of them in action, but it's not the exclusive focus of the video.
I've been subscribed to this guy, Paul Gregg, on YT for like ten years. He builds roller coasters in his backyard for his grandkids and goes over all the physics and design of them. They actually loop back around to the start unlike the one in this post where it seems like you need to haul the cart back up to the top. Very cool stuff