Named a Chicago landmark in 2002, Chicago's Union Station was designed by Daniel Burnham and successor firm Graham, Anderson, Probst & White and completed in 1925. The Great Hall is considered to be the station's main attraction with its 219-foot-long barrel-vaulted skylight that soars 115 feet above the ground. Due to extensive leaks in the existing skylight, Union Station hired Berglund to construct a new, higher performing skylight over the original system.

The primary challenge of this project was to successfully perform the work without disrupting the station's daily operations. While Berglund was installing the skylight above, an estimated 130,000 Metra and Amtrak commuters passed through the great hall directly below. To ensure work didn't interfere with the commuters, Berglund installed a Quick Deck system below the entire existing skylight. This system hung from the skylight's structural steel beams so no scaffold legs would take up valuable space on the ground.

To preserve the important historic features of the building, the existing skylight system was refinished, reglazed and left in place. The new, high-performing skylight was constructed five feet above the original and increased natural light by approximately 50 percent.

Because of continued water leaks, the interior plaster in the Great Hall was also in need of restoration. Once the new skylight system was in place, eliminating the risk of further leaks, Berglund pivoted to restoring the Great Hall's plaster, paint, and interior ornamentation.