The whole story is about the construction of a massive tower (thus the name of the story), but it’s so tall that the cars are actually attached to a kind of governor that allows them to descend the spiral without going out of control. And here, the governor breaks, causing the kind of accident that it was intended to prevent. That last panel is really impressive. 

(Heavy Metal issue #92, November 1984 – Page 37 A Second Babel by Swarte)