preferably tubular steel structures that also have mounting surfaces for other components of the platform deck stabilizers 5 and cantilevers 120 shown in fig1 a attach the rear riser beams 3 and nose beams 4 the deck stabilizers 5 connect the ends of the rear riser beams 3 to the ends of the nose beams 4 the cantilevers 110 are horizontal extensions of columns 6 that are provided to establish the height of the platforms 2 each platform 2 has at least two columns 6 which set the height and carry the loads placed on the platforms the columns 6 are biased toward the lateral edges of the platforms 2 and may be canted inwardly at their tops to better withstand load placed on the platforms as described in u s pat no 4 041 655 to pari the combination of the deck stabilizers 5 the nose beams 4 and the rear riser beams 3 provide a mounting surface for decking 8 which is typically made from plywood the plywood decking provides a surface for mounting additional seating components such as seats 9 and provides a substrate for stepping from one platform to another attached to bottom ends of the columns are castor horns 25 a which have channels provided therein for receiving roller wheels 30 the castor horn roller wheel assemblies allow for the linear movement of platforms from an extended to a retracted position and vice versa these features.