Abstract: This invention relates to a method and apparatus for curing concrete products. The apparatus comprises an endless tunnel of a circular nature through which a plurality of interconnected spaced rack sections are moved in a step-by-step manner, each pair of adjacent rack sections forming an enclosure for receiving the products to be cured; and wherein seal means formed on the rack sections and the interior of the tunnel coact to form spaced separate stations about the tunnel into separate stations of which a superheated steam is inserted, a steam is inserted, and cooling air is inserted simultaneously as enclosures are moved into and out of said stations by an enclosure indexing apparatus.