As Carnie Joe said Harley Wenzel of Wenzels Amazements has a couple.
He had one out on his route till about 1990. I used to up and down that one in the mid 80's. It was a gas motor job and we used to call it the flying greaseball. It was a fun ride to run except for a few quarks. No matter where you stopped it one of the tubs would be on the jump. So you either had to run an empty tub, load the other tubs and move the ride so you could load the last tub that was on the jump. Or like Harley had us doing, have the customers get up on a chair so they could crawl up in the tub. The tubs on that ride were huge. You could pack the largest pair of land whales or a half dozen kids in one. I don't think I ever saw any one get off that ride without a smile on their faces, every one loved it. As far as upping and downing it. All I can say is every one is allowed to be a sucker once, what a nightmare. They don't call that show Wenzels Amazements for nothing. I was always amazed that show went up and down with out killing any one.