From June 2025, here's more detail about the yard expansion. They say they're going to cover the 14th St Yard after acquiring the 35th St/Canal St Yard from Union Pacific. Not sure why they'd need to cover the 14th St Yard unless there are future plans to develop on top of the site
https://miprc.org/Portals/0/userfiles/3/...on2.pdf?ver=jpD6YeueuXX1Ra5zyxAwUA%3D%3D