Abstract: A rotary milking platform 1 has a deck 2, a circular upper beam 4 connected to and supporting the deck, a circular lower beam 6 and a series of carriages 5 connected end to end to form a ring between the beams. The platform is formed such that the upper beam 4 is arranged to rest and rotate on the ring of carriages 5 to rotate the deck 2. Each carriage has at least one carriage roller 10, and each roller 10 arranged to rotate on the lower beam 4. Each roller 10 also has a retention flange 11 at only one side. The flanges 11 of some of the rollers 10 are at or adjacent an inner side of the ring, and the flanges 11 of others of the rollers are at or adjacent an outer side of the ring. The rollers 10 of the ring are arranged such that at least one roller is oriented with its flange 11 on an opposite side to another of the flanged rollers immediately adjacent to it. The flanges prevent the carriages from moving off the lower beam 4 when the platform 1 is in use.