The Paternoster system is based on the same principles of carousels or turning tables, with moving fixtures usually automatically operated at the different service stations for mass production of high demand refrigerator/freezer door models.

The only difference compared to carousels or turning tables where the fixtures move around, is that on the Paternoster system the fixtures move on two superposed tracks and the transfer of the fixtures from one track to the other is achieved by special sector-wheels or hydraulic operated pantograph system. With the two superposed tracks, the main advantage is to save floor space.