A method of indexing moulds (2 1, 2 2) using a flaskless moulding machine for producing moulds (2 1, 2 2) and a mould conveyor for carrying and advancing a mould string produced from a plurality of said moulds (2, 2 1, 2 2) received by the mould conveyor from said flaskless moulding machine, said flaskless moulding machine comprising a pressure piston, the method comprising the steps of: i. forming one or more moulds (2 1, 2 2), one at a time, using said flaskless moulding machine, each of said one or more moulds (2 1, 2 2) being added to said mould string while said mould string is stationary, by being brought into contact with said mould string subsequently to being produced by said flaskless moulding machine, and, once said one or more moulds (2 1, 2 2) have been produced and added to said mould string: ii. advancing said mould string, in a single motion, away from said flaskless moulding machine a distance corresponding to the sum of the thicknesses of said one or more moulds using said mould conveyor, characterised by that said flaskless moulding machine assists said mould conveyor in advancing said mould string during a first part of said distance using said pressure piston, by that said flaskless moulding machine assists said mould conveyor in overcoming the static friction for bringing said mould string in motion, by that said mould conveyor advances said mould string a second part of said distance, corresponding to the remainder of said distance, without assistance from said flaskless moulding machine, and by that said pressure piston is retracted for producing one or more further moulds once said mould string has been advanced said first part of said distance so that the pressure piston only travels the first part of said distance, and not the full distance. i. forming one or more moulds (2 1, 2 2), one at a time, using said flaskless moulding machine, each of said one or more moulds (2 1, 2 2) being added to said mould string while said mould string is stationary, by being brought into contact with said mould string subsequently to being produced by said flaskless moulding machine, and, once said one or more moulds (2 1, 2 2) have been produced and added to said mould string: ii. advancing said mould string, in a single motion, away from said flaskless moulding machine a distance corresponding to the sum of the thicknesses of said one or more moulds using said mould conveyor, characterised by that said flaskless moulding machine assists said mould conveyor in advancing said mould string during a first part of said distance using said pressure piston, by that said flaskless moulding machine assists said mould conveyor in overcoming the static friction for bringing said mould string in motion, by that said mould conveyor advances said mould string a second part of said distance, corresponding to the remainder of said distance, without assistance from said flaskless moulding machine, and by that said pressure piston is retracted for producing one or more further moulds once said mould string has been advanced said first part of said distance so that the pressure piston only travels the first part of said distance, and not the full distance. said flaskless moulding machine assists said mould conveyor in advancing said mould string during a first part of said distance using said pressure piston, by that said flaskless moulding machine assists said mould conveyor in overcoming the static friction for bringing said mould string in motion, by that said mould conveyor advances said mould string a second part of said distance, corresponding to the remainder of said distance, without assistance from said flaskless moulding machine, and by that said pressure piston is retracted for producing one or more further moulds once said mould string has been advanced said first part of said distance so that the pressure piston only travels the first part of said distance, and not the full distance.