The lowered flying tables are then positioned onto roll-out units. The roll-out units are placed on the slab directly under the truss. Some roll-out units have wide cylinder flanges to facilitate fitting the truss bottom chord. Other roll-out units are made in a saddle shape that fits the bottom chord of the truss.
The flying table is then tilted and rolled out carefully by four construction workers (step 5, Figure 4.5).