Abstract: A traveling mold for forming a pre-cast, box-like concrete structure has movable frame means for supporting the mold. Inner and outer wall forms of the traveling mold are movable, vertically and transversely, away from a formed reinforced concrete wall section, after the wall section has hardened sufficiently to be self-supporting. A method for forming a pre-cast reinforced concrete building structure having a floor and at least one upstanding wall, using the traveling mold, is also described.