According to Curbed Chicago:
A new permit from the city has signaled that workers are preparing to move inside Chicago’s massive Old Main Post Office structure to begin rehabbing the Art Deco building’s lobby. Workers were first spotted on the scene back in October of last year to begin exterior facade repair and restoration. Having stood vacant for over 20 years and suffered through multiple fires and the neglect during that time, the overhaul of the building is expected to be a $500 million undertaking.Everyday (and weekend) it seems like there is significant action at the building. Last weekend we saw a helicopter actively buzzing around moving stuff around. Good to see some progress at this place!