A stacking mechanism and method brings batches of articles from a shingled formation on a conveyor to a vertically stacked formation without stopping the progress of any of them. Shingled articles are pushed forward from behind by a pusher at a speed greater than that of a conveyor on which they are supported while at the same time a slower-moving obstruction is erected in their path offering a vertical rear wall. The articles successively align against the rear wall of the obstruction until when the longitudinal distance between the pusher and the obstruction has become substantially the same as the length of the articles, so that all of a batch of shingled articles must have been stacked, the obstruction is withdrawn and the stack is driven on by the pusher. Hooks may travel at the same speed as the conveyor and engage over a trailing edge of the last article in a shingled batch of articles to help define the end of the batch.