in a method and an apparatus for producing pipes having a transverse profile from thermoplastic material , mold segment halves are used on a molding path and are circulated in pairs . a main conveying device is provided for returning the mold segment halves , the main conveying device being designed like a gantry crane . a conveying bridge encompassing the molding path is provided with two conveying carriages which are displaceable at right angles to a direction of production and in opposite directions relative to each other and to which is in each case attached a downwards facing conveying arm comprising a holding device for in each case one mold segment half . downstream of the downstream end of the molding path are provided parking positions for additional mold segment halves . disposed downstream of the molding path is an auxiliary conveying device which is provided for removing the additional mold segment halves from the molding path in order to subsequently return them to the parking positions .