The age-old argument of top-versus bottom-driven horizontal carousels comes up all too frequently (at least among carousel people). You may think it doesn’t really matter that much but in fact, it makes all the difference in the world. Supporting something from underneath makes sense. After all, trains, cars and most rolling objects are bottom-supported. Yet, the best designed horizontal carousels in the world are top-supported units that outperform bottom-supported units in both speed and efficiency. How can that be?