A continuous casting installation of endless track type comprises a plurality of mould blocks (1) connected together in two endless tracks (2). The two tracks have runs which are disposed in opposed parallel relationship and each mould block (1) is of generally L-shaped cross section of which each limb (1a, 1b) cooperates and forms a seal with a limb of an associated mould block in the other track when the two said mould blocks are in the cooperating runs whereby the mould blocks in the said runs define a mould cavity (3). In use, the mould blocks in the said opposed runs are moved in the same direction and molten metal is poured into one end of the mould cavity (3) and a casting (5) is removed at the other end. A guide rail (10, 11) is situated within each track and the guide rails are offset in opposite directions from the centre line (1) of the mould cavity in the region upstream of the opposed runs. The guide rails (10, 11) cooperate with the mould blocks and guide them to move towards one another not only in the direction lying in the plane of the two continuous tracks but also in a direction perpendicular thereto whereby there is no risk of the corners of the limbs (1a, 1b) of the mould blocks (1) hitting one another.