Four months later, the engineer finally completed the analysis. That plus subsequent changes during construction, including the addition of cover plates to already erected trusses, added more than 4,000 tons of steel to the original 12,000. As if on skates, the three panels roll off each other toward the park's center. The stacking makes the most of a relatively tight 22-acre site that abuts an overpass on one side and railroad tracks on another. The rolling panels have their own tracks extending along the top of the long sides of the building.
Cables pull the wheel assemblies beneath each rolling panel.
Other guideways without cables run along the tops of the panel interiors. They enable the stacking. The system differs from the one at the Toronto Skydome. That roof takes 20 minutes to open or close. The drums drive the wire-rope systems, called bogies, connected to the wheel assemblies along the north and south sides of the panels.