Abstract: In manufacturing concrete tiles a stiff concrete mass is molded and heavily compacted by means of a rapidly rotating pressing roller on sheet metal molding trays, which during the molding operation are supported by carriers having relief-like supporting surfaces which are generally complementary to the bottom sides of the tiles. The tray carriers form parts of an endless conveyor passing a concrete extruding station, in which the pressing roller is included, the tray carriers being formed as platforms placed freely between a pair of driving chains, to which each platform is connected by one pair of coaxial pivots only. Each platform is composed of two segments, which are hingedly interconnected independently of the chains. When passing the concrete extruding station the tray carrying platforms rest on an endless intermediate belt moving over a stationary supporting bed, through the top side of which pressurized air is supplied in order to reduce the friction.