If you’ve ever waited for a Caltrain at 4th and King, get ready for some serious construction noise. Prologis, the real estate company that basically built its empire by renting warehouses to Amazon, just filed plans to completely transform the 20-acre railyard into what they’re calling “SF Railyards” , and honestly, it’s a pretty ambitious project.

We’re talking 8 million square feet of development spread across two decades. The centerpiece is an 850-foot tower that would become the second-tallest building in San Francisco. That’s taller than the Salesforce Tower… just kidding, but it’s still massive. The tower would replace the current station, which is wild considering Caltrain will remain operational the whole time.

Here’s what the project actually includes: about half would be commercial space (offices, retail, maybe even a hotel), while the other half would house up to 2,500 new units. And yes, the Bay Area needs more housing, so that’s worth noting. The redeveloped site would also feature some public perks , a promenade along Townsend Street, a plaza at 5th Street, and a park on 6th Street. So it’s not just towers and office buildings; there’s actually some public space in the mix.

The timeline here is important. First, Caltrain gets upgrades to its rail infrastructure. Then Prologis builds the tower. But here’s the kicker: they won’t start on the rest of the project until “The Portal” , a separate plan to extend Caltrain service downtown to the Salesforce Transit Center , is actually complete. That’s because the railyard needs space for storage, which they’re planning to relocate offsite. So full buildout could genuinely take 20 years.

Caltrain says they don’t expect fare increases from this project, and service will remain a priority during construction. That’s the kind of thing you want to hear when your commute is about to get messier. Mayor Daniel Lurie called it a “bold vision”, which in politician-speak usually means he’s optimistic about it.

Prologis is planning to raise both public and private funding for the project, which now heads into environmental review. If approved, this could be one of the biggest San Francisco development stories in years. The company’s basically betting billions that San Francisco’s comeback is real , and that people actually want to live and work down by the waterfront.

For those of you commuting on Caltrain or just walking through that area, prepare for a very different neighborhood in the coming years.