After nearly 20 years of vacancy, the big redevelopment plans for Chicago’s Old Main Post Office have turned smaller… much smaller.

Investor Bill Davies’ latest idea for the landmark building along Congress Parkway now involves micro apartments.

Davies plans to convert the space into 300 small apartment units ranging from 280 to 600 square feet, according to Ellen Phillips, managing broker of Loop Apartments. Called The MicroChicago at The Old Post Office, the apartments would range from studios priced at $1,140 to two bedrooms priced at $2,400 and would be leased by Loop Apartments, a Chicago-based brokerage, Phillips said.

The latest idea is a big shift from the major redevelopment plan first proposed in 2011. That $1.5 billion project aimed to turn the building into a home for high-end retail, a new hotel and a residential development. It also included a 120-story tower that would occupy the space between the post office and the Chicago River and would surpass the Willis Tower as the tallest building in the city.

Davies, who gained control of the property in 2009, hoped to attract international investors to pay for the project, but the development plans later dissolved.

It’s not clear how Davies will fund the new scaled back project plan. Tiny apartments are popular in places like New York City, but have yet to become popular in Chicago.

Davies hopes to begin construction in March of this year and have the building completed by mid- to late-2016, Phillips said.